DOS Times Vol 25 NO. 3

Volume 25, No. 3 Nov-Dec, 2019

Focus: PACD Management Cracker
What's New: Corneal Neurotisation for Neurotrophic Keratitis
Basics: Contrast Sensitivity: Essential but often Ignored
PG Corner: Keratoconus





DOS Times Editorial Board

Neha Midha Barkha Gupta



Dear Members,

In this arena of “Corona Times” it is important to stay safe, stay healthy and
stay at home. Keeping in view of pandemic of COVID-19, we are postponing
the Annual meeting of the DelhiOphthalmological Society this year that is
2020, until the situationisclear.

To help the DOS members we have written letters to the Finance Minister,
Health Minister of Delhi and also Lieutenant Governor of Delhi to help DOS
members regarding the various aspects which includes moratorium on
statutory dues, temporary cessationof EMI payments and interest, subsidy on
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payments (CGHS, ECHS etc.) and TPA payments of government and insurance
companies for services rendered in the past, at the earliest. Further letters
have also been written regarding interest free loans to health careproviders
for the next one year and immediate rectification and refund of Advance Tax
(last instalment paid by us in view of falling earning in March 2020).

This is also for everyone's attention that E version of DOS Times is being sent
now because of logistic issues with printing and courier of the DOS Times as
well as Delhi Journal of Ophthalmology. As and when things get better, we will
send hard copies.

In order to our members aware of the Covid 19, several articles will follow.
The next DOS Times is dedicated to the CORONA and will have information
about all you want to know about CORONA.

Further, many nursing homes, in the city are due for renewal of registration
with the DGHS and have applied for the same. Letters have been issued by
the authorities regarding the same. We have appealed to the directorate
that, in order to minimise the inconvenience to medical professionals
running nursing homes, to kindly extend the registrations for another term.
Similar unprecedented measures like extension of the

EMIs due date, income tax due date and the financial year have already been
done and hence they should also relent.

These are tough times and these shall pass soon. Stay Safe, Stay healthy and
stay at home!

Best wishes

Focus

Prof. Ramanjit Sihota Focus
Dr. S.R. Krishnadas
PACD Management
Dr. SS Pandav Cracked
Dr. Sirisha Senthil
Dr. Shamira Parera Prof. Ramanjit Sihota: MD, FRCS, Prof. of Ophthalmology, Dr. Rajendra Prasad Centre for
Dr. Ronnie George Ophthalmic Sciences, All India Institute of Medical Science, Ansari Nagar, New Delhi, India.

Dr. S.R. Krishnadas: DO, DNB, Senior Consultant, Glaucoma Services, Aravind Eye Hospital,
Madurai, India.

Dr. Surinder Singh Pandav: MS, Prof. Ophthalmology, Glaucoma Services, Postgraduate
Institute of Medical Education and Research, Chandigarh, India.

Dr. Sirisha Senthil: Consultant - VST Centre for Glaucoma, L.V. Prasad Eye
Institute, Kallam Anji Reddy Campus, Banjara Hills, Hyderabad, India.

Dr. Shamira Parera: MBBS, (Hons), FRCOphth, Associate Professor, Glaucoma
and Cataract Services, Singapore National Eye Centre (SNEC), Singapore.

Dr. Ronnie George: Senior Consultant, Glaucoma Services, Sankara Nethralaya,
Professor, Elite School of Optometry, Director-Research, Medical and Vision
Research Foundations, 18, College Road, Chennai, India.

Dr. Dewang Angmo: MD, DNB, FRCS, FICO, MNAMS: Assistant Professor Dr. Dewang Angmo
of Ophthalmology, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All
India Institute of Medical Sciences, New Delhi, India. Associate Editor, DOS
Times interviewed the above panelists.

Primary angle closure disease (PACD) is a preventable cause of irreversible blindness
which currently impacts nearly 27million people in India, in its entire spectrum
comprising of Primary angle closure suspect (PACS), Primary angle closure (PAC) and
Primary angle closure glaucoma (PACG). The management of eyes with PACD is complex
and may not be one well-defined algorithm which “best fits” to manage all the cases.
Surgical decisions have to be made on case to case basis and are dependent on multiple
factors including stage of disease, patient income (affordability for life long medications)
and feasibility for regular follow up, surgeon training and availability of tertiary care set-
up to manage complications. In this focus, we have interviewed speakers from India and
abroad to discuss on the management of this burning blinding topic!

Dr. Dewang Angmo: What are the special considerations for performing
Trabeculectomy in PACG?

Prof. Ramanjit Sihota: 1. A prior iridotomy should be done to see if subsequent medical
control is possible. 2. Surgery should be done in a quiet eye

Preop Mannitol is essential to deturgesce the vitreous, if IOP is still high a paracentesis is
a must before making the osteum

Dr. S.R. Krishnadas: In primary angle closure glaucoma, it is preferable to avoid
penetrating filtering surgery, to the extend it is practical and possible. Over filtration following
trabecuelctomy can cause serious and potentially blinding complications. Excessive filtration
can cause shallow chambers with forward shift in the effective lens position which can trigger
aqueous misdirection and aggravate angle closure. This can cause further apposition of the

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Focus

peripheral anterior chamber angles and compromise filtration. deep block excision more anterior (as the limbus is narrow)
Hypotony from unrestricted filtration can also precipitate - this would prevent damage to CB during the iridectomy,
choroidal detachments and supra- choroidal haemorrhage. avoid sudden intraoperative hypotony, reformation of
Surgical technique and post operative management has to anterior chamber if needed, releasable sutures to help prevent
be meticulous to prevent any excessive filtration to avoid early post op Hypotony and shallowing of the anterior
hypotony and related adverse events. One needs to ensure chamber, instillation of cycloplegicson tableto help deepen
tight scleral flap closure with no scleral or conjunctival the anterior chamber and subconjunctival steroids and
buttonholes or needle track to avoid bleb / wound leak in Atropine to decrease inflammation and induce Cycloplegia
the post operative period. One also need to meticulously and prevent aqueous misdirection.
err on tighter scleral flap to avoid over filtration, especially
in the first few weeks following trabecuelctomy. Since Dr. Shamira Parera: Pre operatively, it is worthwhile
the crystalline lens has now been proven to play a pivotal ensuring with gonioscopy that the position where you plan to
role in pathogenesis of relative pupillary block and angle perform the sclerostomy is free from PAS. Intraoperatively,
closure, it is preferable to combine lens extraction by phaco surgery can proceed as usual, but in short phakic eyes it
emulsification with trabeculectomy even if lens changes are may be worthwhile giving atropine to reduce the chance
minimal or non-existent (clear lens extraction). I personally of malignant glaucoma which is more common in these
do not recommend releasable sutures for flap closure in eyes. Post operatively, short eyes may be more prone to the
angle closure glaucoma, since it is necessary to release within formation of choroidal effusions rather than maculopathy.
1-2 weeks to ensure its effectiveness. However, in eyes with Otherwise, complication rates are considered equivalent in
angle closure, suture release / laser suture lysis needs to be POAG and PACG.
performed very discretely after carefully considering the IOP,
target pressure required and conjunctival wound healing. Dr. Ronnie George: In these eyes it is advisable
Since laser suture lysis can often be performed effectively to ensure there is a patent laser iridotomy pre-surgery.
even after several weeks or months after trabeculectomy Also ensure that the IOP is controlled pre-op. It is safer to
with adjunctive mitomycin, fixed scleral flap closure, administer intravenous mannitol pre –op and ensure that
rather than releasable sutures are preferable and allows you have a soft globe prior to start of surgery. I would
modulation of filtration even several months after surgery, consider placing pre-placed sutures on the trab flap and aim
minimizing over filtration. Early cataract / lens extraction for tight closure with releasable sutures. Also check that the
alone without trabeculectomy can also significantly reverse anterior chamber is formed well at the end of surgery with
angle closure and control IOP in eyes with mild to moderate no conjunctival edge leak. I prefer to administer a drop of
angle closure glaucoma, without risking trabeculectomy. cycloplegic at the end of surgery.
Complications are also higher following trabeculectomy /
Combined procedures in advanced angle closure glaucoma. Dr. Dewang Angmo: What is your technique of
In eyes with advanced visual field loss threatening fixation, releasable sutures and when do you prefer to remove it?
Micropulse Cub Cyclo laser can either be used as a stand-
alone procedure or combined with cataract extraction, Prof. Ramanjit Sihota: ‘Box’ type sutures, a
instead of trabeculectomy to minimize risk of hypotony and modification of Wilson’s technique. 7- 14 days after surgery,
consequent complications. when AC is formed, IOP is normal and bleb mildly elevated.
Earlier if bleb is flat or shows vascularization.
Dr. Surinder Singh Pandav: In angle closure glaucoma
the anterior chamber is shallow, which may be associated Dr. S.R. Krishnadas: In our practice, we follow
with shorter axial length and or relatively thicker crystalline conventional technique of releasable sutures commonly
lens. Thus trabeculectomy has an inherent risk of further described. We prefer to remove releasable sutures in primary
shallowing of anterior chamber. These eyes are also at a open angle and exfoliative glaucoma within a week to 10
higher risk of aqueous misdirection. During surgery avoid days and in secondary glaucomas within a week of surgery,
rapid or sudden decrease in IOP to avoid choroidal effusion provided there is no evidence of over-filtering blebs. Due to
/ haemorrhage and subsequent shallowing of AC. Keep the conjunctival scarring, it is not possible to release the sutures
AC formed as far as possible during surgerynand have a after two weeks even if anti fibrotics like Mitomycin have
tighter closure of the scleral flap. Aim to have a well formed been used intra operatively. If filtration is deemed sufficient,
anterior chamber at the end of surgery. A drop of cycloplegic releasable sutures may be left behind and cut flush with
agent at the end of surgery helps relax ciliary body and form corneal surface after a few weeks. We prefer not to use
AC. releasable sutures in angle closure glaucoma.

Dr. Sirisha Senthil: Considering the intraoperative Dr. Surinder Singh Pandav: Releasable sutures
challenges and postoperative complications in eyes with are used to have a tight closure of the scleral flap so as to
trabeculectomy, the precautions taken are: avoid hypotony and related complications in the early
postoperative period. I prefer to have a fixed suture at the
Pre-op Mannitol to help decrease the IOP, a little apex of the triangular scleral flap and two releasable sutures
anterior dissection of the scleral flap into clear cornea with on either side. I start on the scleral side just outside the limits
of the partial thickness scleral flap by passing a 10-0 nylon

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Focus

suture from sclera to cornea across the limbus. Then reverse Failed trabs or secondary glaucomas may require
the direction and pass it from cornea to the middle of the additional MMC application subscleral if there is scleral
scleral flap. Finally I suture the scleral flap on one side tightly fibrosis, with 0.4mg/ml.
to the corresponding edge of the scleral bed using a 4 loop
single knot. Same procedure is repeated on the other side of Dr. S.R. Krishnadas: When used with sponges
the flap. After tying the suture, I inflate the AC with balanced subconjunctivally, we prefer 0.4 mg/ ml MMC ( 0.04%) for
salt solution and check for egress of fluid around the flap. 2 minutes in primary glaucomas. In secondary or refractory
There should be no or very little fluid flow and AC should glaucoma, 0.04% MMC is used for 5 minutes. When used as
remain formed. sub conjunctival injections, we prefer 0.1 mg /ml MMC in
primary glaucomas.
If the bleb is formed and adequate IOP lowering is
achieved, there is no need to release the suture and it can Dr. Surinder Singh Pandav: I use 0.2mg% of MMC for
be left in situ for a long time. If the bleb is not forming and 2 minutes applied using three 1x2mm sponges. Sponges are
IOP is high, avoid releasing suture in the first 3-4 days placed under Tenon’s capsule just posterior to the dissected
postoperatively. Try gentle eye massage to form the bleb and flap. A good wash is given with BSS to the area of application
give topical anti-glaucoma drugs to lower IOP during this after removal of sponges. Most surgeons these days prefer
period, if required. My preferred time frame for releasing lower dose & exposure time and wider area of application
sutures is between 5-10 days - lower side if the bleb is not avoiding the limbal area.
formed and upper side if enhancement of filtration is
required. Enough healing takes place by 5-7 days so risk of Dr. Sirisha Senthil: 0.04% for 2 minutes.
wound leak on releasing suture is low. Also within the 2nd
week adhesions around the filtration area are not strong and Dr. Shamira Parera: 0.2mg/ml injected into the
are amenable to bleb massage. Bleb extent can be increased Tenon’s tissue to expand it anteriorly. Aim for 0.1-0.2mls
by releasing sutures coupled with gentle massage over the and spread it diffusely. The aim should be to bring forward
bleb. the Tenon’s tissue [so later it can be neatly apposed to the
limbus to aid watertight closure], and then wash with 50mls
Dr. Sirisha Senthil: I place loop releasable sutures. of balanced salt solution.
Usually take one apical fixed suture (just apposing), and
two releasable sutures on either side of a triangular flap. Dr. Ronnie George: I use 0.4mg/ml for 1 minute
The releasable sutures are tight. One releasable suture is under the conjunctival flap.
removed at 1 week and 2nd one based on the IOP and the
bleb features, at either week 3 or later/ or trim it if there is no Dr. Dewang Angmo: What are your indications
need to remove. for performing lens extraction in PACG / PAC / PACHT?

Dr. Shamira Parera: I prefer one fixed suture and one Prof. Ramanjit Sihota: I would do a lens extraction
4 throw releasable suture at the two corners of my scleral only if a visually significant cataract is present.
flap. Releasable sutures can be loosened by way of digital
ocular massage to fill the bleb and the 4 throws allow some Dr. S.R. Krishnadas: In these situations, if lens has
slackening. Alternatively, external suture manipulation with early cataract changes, we prefer lens extraction by phaco
non-toothed forceps can allow more flow too. The resistance emulsification. If lens is clear or if patients prefer to defer
in the subconjunctival space can be tested by allowing the bleb cataract surgery, we suggest Laser Iridotomy. We still do not
to fill with digital massage, if it fills too easily and diffusely, it suggest clear lens extraction in these clinical situations.
may be premature to release the suture. Although, there are
no fixed guidelines, the timing of removal is dependent on Dr. Surinder Singh Pandav: Indication for surgery in
surgeon’s experience, amount of scarring and related to the these situations is visually significant cataract. In PACG /
expectations for the IOP in the longer term. The releasable PAC I like to do early cataract surgery especially if the lens
suture should be removed before the laser suturelysis of the is thick and / or axial length is on the lower side. If IOP is
fixed suture. After a prolonged period, it becomes difficult to not well controlled, I prefer to do cataract surgery first and
remove the releasable suture due to subconjunctival scarring monitor IOP.
and it is more likely to snap.
Dr. Sirisha Senthil: I prefer only cataract surgery in
Dr. Ronnie George: I use two three throw releasable eyes with PACG with medically controlled IOP, irrespective
suture on a triangular scleral flap with the trailing end buried of the severity (early moderate or severe glaucoma).
in the cornea. I prefer to release the sutures in the second
week after surgery but this can vary depending on the degree In all PAC (with normal IOP) only cataract surgery.
of filtration.
Only cataract surgery in all PAC with ocular
Dr. Dewang Angmo: What is your preferred hypertension and IOP controlled medically, In PAC with
concentration and dosage of MMC in Trabeculectomy? ocular hypertension, high IOP despite medical treatment-
if lens vault is high or has occludable angles opening on
Prof. Ramanjit Sihota: Primary adult glaucomas – indentation then only cataract surgery. In PAC with ocular
POAG/PACG – 0.1/0,2mg/ml for 1 minute subconjunctival hypertension, high IOP despite medical treatment with
significant angle synechially closed with prefer combined
surgery.

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Dr. Shamira Parera: The Eagle study concluded that combination of watertight incisions and increased infusion
clear lens extraction is preferable to initial laser peripheral pressure allows for maximum deepening of the anterior
iridotomy on a quality of life basis and marginally on IOP chamber via fluidics to facilitate safe emulsification.
lowering and fewer additional operations in eyes with PACG
or PAC with IOP>30mmHg. In instances where extremely shallow chambers or
high intra operative pressures preclude safe emulsification,
Dr. Ronnie George: I would consider removing a one can approach vitreo retinal surgery to perform pars plan
cataractous lens in an eye with PACG/PAC with residual vitrectomy, which lowers intra ocular pressures significantly
closure post laser iridotomy or if along with a planned and deepens anterior chamber significantly.
trabeculectomy. In case of PACS I would consider lens
extraction in a visually significant cataract. Dr. Surinder Singh Pandav: In these eyes the AC
is shallow and the lens might be relatively thicker. So the
Dr. Dewang Angmo: What are the special working space for phaco-probe is less. Special care should be
considerations for performing lens extraction in PACS/ taken to prevent corneal endothelium. Intraocular pressure
PAC/PACHT/PACG? should be well controlled preoperatively. If not controlled,
then before surgery lower IOP with systemic medication –
Prof. Ramanjit Sihota: Use of intravenous Mannitol, oral Acetazolamide or intravenous inj Mannitol. These eyes
oral acetazolamide and hyperosmotic agents including oral at a higher risk of corneal endothelial damage, capsular
glycerol to reduce intraocular pressure and dehydrate the rupture, pupillay block and aqueous misdirection. In
vitreous. established glaucoma I don’t use multifocal IOLs and avoid
a toric IOLs if filtering is likely to be needed in near future.
Enter the anterior chamber (AC) with well controlled
IOP only. To keep the AC formed throughout the phaco to Dr. Sirisha Senthil: Would prefer a topical cataract
prevent endothelial cell loss and keep the iris from prolapsing surgery. The challengesin performing cataract surgery in
frequently. these eyes are shallow anterior chamber, reduced endothelial
cell countand small pupils. We would consider use of high
Dr. S.R. Krishnadas: Precautions taken to deepen viscousviscoelastic to deepen the anterior chamber for a safe
anterior chamber can provide a wide margin of safety and cataract surgery. Try to attain good pupillary dilatation, in
prevent damage to the corneal endothelium and posterior case of small pupils - pupillary stretch by various techniques
capsule, while facilitating safe capuslorrhexis of the anterior would help to achieve adequate capsulorrhexis. The rest
capsule. Accurate biometry is crucial and Holladay 2 formula of the steps of good hydrodissection and multiple small
is more effective in eyes with shallow chambers and more nucleus fragments would help safe cataract surgery. In the
anterior effective lens position to prevent any refractive bag intraocular lens is mandatory.
surprises.
Dr. Shamira Parera: Avoid conjunctival incisions
Use of oral acetazolamide, and hyperosmotic agents to reduce the risk of scarring even if distant from a future
inckusing oral glycerol and intravenous Mannitol reduce intra trabeculectomy site. Hence, phaco is preferred to SICS/
ocular pressure and dehydrate the vitreous with posterior ECCE.. Long tunnels and a preferably 3 step incision are
movement of the crystalline lens, creating more anterior helpful in maintaining the AC. Viscodispersive agents help to
chamber space for intra ocular manipulation necessary for protect the corneal endothelium whilst cohesive viscoelastics
capsulorrhexis and nuclear emulsification. Iris hooks may be may help deepen the AC. The shallow AC may be challenging
used to manage small, rigid pupils or floppy iris. but judicious use of techniques to limit endothelial damage
should help in the longer term. The correct formula should
Intra operatively, capsulorrhexis is often difficult be chosen for these shorter eyes and care should be taken
due to shallow chamber and a convex anterior lens surface to look for subluxed lenses with imaging if needed. Some
with risk of capsular tears. This can be addressed by use of have small pupils so a low threshold for iris hooks should
high viscosity ophthalmic visco- surgical devices (OVD) to be maintained. Pre operatively, there is a need to manage the
create and maintain anterior chamber space. It is ideal to use IOP well to reduce the chance of malignant glaucoma which
highly cohesive OVD , such as sodium hyaluronate. It is also is more common in short eyes. If particularly worried we
preferable to use 1 mm side port corneal incisions to perform may atropinise the patient post op to mitigate the risks of
rhexis , since distorting the main corneal incision or causing this happening.
it to gape can collapse the anterior chamber with escape of
the OVD. It is important not to over inflate anterior chamber Dr. Ronnie George: Such eyes are small eyes with often
by excessive OVD or overfill since this can cause repeated iris crowded anterior segments. The surgeon should anticipate
prolapse interfering with introduction of instruments and this. Keep in mind that orbital volumes can also be small if a
phaco probe into the anterior chamber. block is planned using minimal volume is advisable. Ensure
that the globe is soft pre surgery and the pupil is adequately
During phacoemulsification, the surgeon can raise the dilated. Since the anterior chamber volume avoid overfilling
bottle height to increase the infusion pressure and further with viscoelastic or BSS since this can cause a. IOP spike on
deepen the anterior chamber. The surgeon can decrease table with iris prolapse.
outflow by lowering the flow rate, which can help increase
the space in which to work within the anterior segment. The

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Focus

Dr. Dewang Angmo: Role of combined phaco aqueous misdirection. In the setting of uncontrolled IOP
with Trabeculectomy surgery in PACG? especially post an acute angle closure crisis the combined
procedure can be challenging.
Prof. Ramanjit Sihota: Patients with a visually
significant cataract and mild to moderate glaucomatous Dr. Dewang Angmo: How to manage malignant
damage. glaucoma in PACG in (a) Phakic eye, (b) Pseudophakic
eye?
Dr. S.R. Krishnadas: In eyes with primary angle
closure glaucoma with IOP not in the target range, with Prof. Ramanjit Sihota: a) Phakic–Maximal topical
maximum tolerated medical therapy, post laser Iridotomy, we glaucoma medications, with full doses of Diamox, mannitol,
recommend trabeculectomy combined with lens extraction atropine, phenylephrine. If IOP over 28mmHg after 1 day,
by phaco. In eyes with PACG, when filtering surgery is laser zonulolysis if iridotomy large. Else phacoemulsification
indicated, we recommend combined phaco trabeculectomy, with vitrectomy.
even if lens has minimal changes or is clear.
b) Pseudophakic eyes – Medications as above.
Dr. Surinder Singh Pandav: I usually avoid a NdYAGcapsulotomy with hyaloidotomy first. Later a
combined surgery in PACG. Combined surgery is more vitrectomy if IOP is still not controlled.
unpredictable in terms of IOP control and a higher rate of
complications has been reported as compared to phaco In both, Atropine for 6 months to a year (1% Ointment
alone. Cataract surgery alone lowers IOP in majority of these BD).
patients and also the number of antiglaucoma medicines
required to control IOP has been reported to go down. If IOP Dr. S.R. Krishnadas: Definitive management for
is not controlled adequately after phaco, filtering surgery can malignant glaucoma is complete pars plana vitrectomy in
be done any time. both phakic and pseudophakic eyes. Vitrectomy needs to be
combined with lens extraction or lensectomy in phakic eyes.
Dr. Sirisha Senthil: In eyes with uncontrolled IOP
with significant cataract, combined surgery is indicated. Dr. Surinder Singh Pandav: Malignant glaucoma
The advantages being decrease in IOP, deepening of is difficult to manage. I would start with conservative
anterior chamber and improvement in vision. However management that included topical as well as systemic IOP
post-operative inflammation in combined surgery has to lowering medications. Give topical steroids and cycloplegics
be anticipated specially when pupillary stretch or other to control inflammation and relax ciliary body. Make sure
manipulations areneeded during surgery and treatment there is a patent iridectomy / iridotomy. These measure
with higher frequency of steroids and cycloplegics has to will help in most of cases in resolving malignant glaucoma.
be instituted. Only Phacoemulsification might help in eyes In psuedophakic eyes we can do Nd YAG laser posterior
with significant appositional closure. If a trabeculectomy is capsulotomy and disrupt the anterior vitreous phase. If these
indicated, the threshold for combining a cataract surgery measure don’t work then next step is do surgical iridectomy
would be low. + zonulectomy + anterior hyaloidectmy with a vitrectomy
cutter. In some cases you might have to do complete pars
Dr. Shamira Parera: There are financial plana vitrectomy. In phakic eyes conservative measures
usually work. In interactable cases we may have to do
benefits and convenience to the patient with a combined cataract surgery with iridectomy and Zonulo-hyloidectomy
at the same time.
operation. There may be logistical benefits and economies
Dr. Sirisha Senthil:
of scale to the centre of doing combined surgeries. Logically
Phakic Eye
the lens plays a very important part in PACG pathogenesis
Pseudophakic Eye
and its removal offers the chance to improve the vision of
First line treatment:
the patient, however, evaluating the lens component is not
• Topical cycloplegics and mydriatics
easy. Generally, the risks of cataract extraction are low with
• Topical and oral aqueous suppressants
experienced surgeons, and combined surgery can offer
• Topical steroids
options to target emmetropia, reduce astigmatism and add
Second line treatment: Anterior approach Irido-zonulo-
on multifocality. However, this must be balanced against hyaloido-vitrectomy (IZHV).

the poorer prognosis of combined surgery in terms of IOP Third line treatment: Pars plana vitrectomy/ core
vitrectomy with IZHV.
control due to the additional inflammation from the phaco.
Dr. Shamira Parera: In a phakic eye, it is difficult to
Refractively, the results of sequential surgery or combined diagnose, as it could simply be a lenticular level of block. This

surgery are similar so we have a tendency to be pragmatic

and proceed to combined surgery commonly in PACG. It

may also reduce the risks of malignant glaucoma.

Dr. Ronnie George: Combining the Trabeculectomy
with a phaco has the advantage of providing a deeper
chamber post and intraoperatively. This makes it easier
to manage a post operative shallow anterior chamber of

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Focus

could lead to the other levels of block too eg ciliary block and bottle height (IOP) and remove the viscoelastic thoroughly
pupil block. Simply put, the management seeks to provide at the end of surgery. Postoperatively monitor IOP, bleb area
a free and persistent communication between the anterior for height, extent and vascularity. AC inflammation should
chamber and the vitreous cavity, however, in the presence be treated promptly. I don’t put multifocal IOLs and avoid
of a crystalline lens, this can be challenging, especially when toric IOLs in eyes with filtering blebs.
the most definitive treatment is to perform a pars plana
vitrectomy without touching the lens. In a pseudophakic Dr. Sirisha Senthil: Thorough wash of viscoelastics,
eye, this is easier and the management can be medical- with although a self sealing small incision, main incision needs
atropine, surgical - with pars planar vitrectomy or with suturing to prevent postoperative leak or anterior chamber
laser- transscleral cyclophotocoagulation to rotate back the shallowing.
ciliary processes. Also, you might be able to to perform a
YAG hyaloidotomy via a LPI with/or without a posterior Dr. Shamira Parera: These are the same as for POAG.
capsulotomy. But this is not straightforward. The end point Care must be taken to perform the biometry correctly as
would be when the AC deepens. The management does not in low IOP eyes, the axial length may be underestimated.
differ from malignant glaucoma in POAG. Intraoperatively, antifibrotics can be injected at the end of
the case to lessen the risk of bleb failure from the increased
Dr. Ronnie George: I would always try conservative inflammation. The timing of the phaco at least 6 months after
management after ensuring that there is no pupillary block the trabeculectomy is preferred as it lessens it failing.
component or choroidal effusion first using hyperosmotic
agents based on the IOP level, aqueous suppressants and Dr. Ronnie George: Cataract surgery in these eyes can
cycloplegics. In parallel assess the cause for the malignant be challenging because of the crowded anterior segment, a
glaucoma – wound leak, over filtration, etc. If conservative potentially compromised cornea (if the post trabeculectomy
management does not reverse the malignant glaucoma in a period has been complicated), posterior synechiae and
phakic eye consider a vitrectomy from the posterior approach sometimes zonular compromise. A good pre-operative
+ lens extraction/phaco and ensure that the anterior hyaloid evaluation and careful intraoperative assessment are
is opened creating a communication from the anterior important.
chamber to the vitreous cavity (irido –zonulo- hylaoidotomy)
as well as address any wound leak or over filtration that may Dr. Dewang Angmo: Role of SLT in PACG?
be the inciting event. For pseudophakic eyes I would attempt
a YAG laser vitreolysis through the surgical iridectomy. This Prof. Ramanjit Sihota: Very limited. As the spot size is
is very often successful in reversing the attack. Long term large, experience with ALT showed a 3-4 mmHg fall in 1/3rd
cycloplegics may be required to prevent a recurrence. of patients.

Dr. Dewang Angmo: What are the special Dr. S.R. Krishnadas: SLT may have a temporizing
considerations for performing cataract surgery after effect on reduction of IOP in PACG, if the angle is at
Trabeculectomy in PACG? least partly open and trabecular meshwork is free of any
peripheral anterior synechiae in some quadrants. SLT may
Prof. Ramanjit Sihota: Keeping in mind the smaller reduce need for medications or the number of medications
AC, floppy atrophic iris and endothelial changes already required to achieve target eye pressures and may thus
present, IOP should be well controlled prior to phaco and the improve adherence and reduce cost of medical therapy. Long
AC maintained throughout. In advanced glaucomas postop term effects of SLT in angle closure glaucoma is not known.
Diamox and timolol may be given for 3 – 7 days.
Dr. Surinder Singh Pandav: Yag Laser peripheral
Dr. S.R. Krishnadas: Most eyes in PACG following iridotomy is recommended in all patients of PACG. SLT is
trabeculectomy are often complicated by cataracts with small not used as a primary therapy. However, it can be used as
pupils, posterior synechiae and shallow anterior chambers. a supplemental therapy to lower IOP following LPI. Pre-
In general, principles followed for cataract surgery in shallow requisite for SLT in PACG is visibility of trabecular meshwork
chambers in PACG may also be applied. Lens extraction at least in 2 quadrants on gonioscopy and a patent LPI. In our
is likely to improve IOP control further. It is however, experience more than 65% eyes achieve IOP reduction of 20%
important to closely follow up since ocular pressures may or more at one year following SLT for PAC or PACG. SLT is a
occasionally increase due to bleb fibrosis. one-time procedure and is easy to do without any significant
complications.
Dr. Surinder Singh Pandav: Cataract develops faster
after filtering surgery and some patients would need cataract Dr. Sirisha Senthil: No experience.
surgery following trabeculectomy. Cataract surgery should
be delayed as far as possible in an eye with a bleb as there is Dr. Shamira Parera: SLT may be difficult to perform in
a risk of bleb failure after cataract surgery. I would wait for PACG eyes post LPI as little of the circumferential angle may
at least 3 – 6 months before doing phacoemulsification after be amenable to laser. Furthermore, placing the laser spot
trebeculectomy. During surgery avoid handling the filtering over the meshwork may be challenging due to the convexity
area. I keep phaco parameters on the lower side especially of the iris. Nevertheless, SLT appears to be a very safe and
effective modality of IOP reduction in eyes with PAC/
PACG after LPI as evidenced by an RCT comparing it to a

www.dosonline.org/dos-times DOS Times - Volume 25, Number 3, November-December 2019 11

Focus

prostaglandin analogue, where both were equally effective Dr. Shamira Parera: Use imaging by way of ASOCT
at 6 months. and UBM to elucidate the mechanism of PACG and direct
treatment at that. As this is an unusual presentation,
Dr. Ronnie George: SLT can be effective in PACG alternative diagnoses should be considered eg uveitic
in eyes with significant areas of open angles post laser glaucoma, neovascular glaucoma, traumatic glaucoma. With
iridotomy. younger patients, one should be more aggressive with the
management in general.
Dr. Dewang Angmo: How to manage/ investigate
PACG in young patients (< 40 years)? Dr. Ronnie George: It is important to rule out a
secondary cause such as a subluxated lens or spherophakia.
Prof. Ramanjit Sihota: Iridotomy in eyes with high It is worthwhile to do a UBM especially if there is plateau iris
risk factors – family history, very narrow angle, secondary component. Many of these eyes have plateau iris which can
causes such as spherophakia or nanophthalmos. Regular sometimes be secondary to iris cysts. Measuring the biometry
review. is also useful . Close monitoring of the angle is important to
look for progressive closure.
Dr. S.R. Krishnadas: Early laser Iridotomy and
maximal medical treatment to achieve target pressures as Dr. Dewang Angmo: What is you indication for
in management of PACG in elderly individuals is preferred. doing Yag PI in PACS patients?
Filtering surgery in young individuals generally have more
adverse outcomes including shallow chambers and aqueous Prof. Ramanjit Sihota: High risk factors – family
misdirection. Lens extraction alone in mild to moderate history of PAC/PACG, one eyed individuals, patients with
glaucoma may manage glaucoma when combined with retinal diseases requiring frequent dilation and those unable
medical treatment. If trabeculectomy is indicated, it is to review.
preferable to combine it with lens extraction to pre-empt
complications like aqueous misdirection. In eyes with Dr. S.R. Krishnadas: In situations where frequent
advanced glaucomatous disc damage, ocular surgeries dilatation is indicated, YAG PI may be recommended
usually is complicated by adverse events like choroidal in eyes with PACS. It may also be suggested in eyes with
effusions and aqueous misdirection. It is preferable to suboptimal visual acuity, where it is essential to dilate the
recommend Micropulsed Cilio ablation in these situations. pupils for a complete retinal evaluation under mydriasis.
Indentation Gonioscopy may offer valuable clues to decide
Dr. Surinder Singh Pandav: Angle closure glaucoma in on management of PACS. The magnitude of pressure
young patients may not be due to pupillary block mechanism. required to indent open the angles is an indirect measure
Therefore cause or mechanism in these patients should be of apposional angle closure. Inability to open the angles on
investigated. Common causes include plateu iris syndrome, firm indentation is an indication for Laser PI. Appositional
iris or ciliary body cysts, nanophthalmos, subluxated lens, closure > 180 degrees of the angle, higher or asymmetric
trauma, uveitis and rarely idiosyncratic response to drugs. A CDR, and IOP consistently > 20-21 mmhg, family history of
thorough clinical evaluation including systemic examination angle closure glaucoma are additional indications for LPI in
will, most of the time, give you the diagnosis. Ultrasound and eyes with PACS.
UBM of the eye is very helpful in establishing the anatomical
basis of angle closure in these eyes. Laser iridotomy may not Dr. Surinder Singh Pandav: We don’t do Yag PI in
be needed or may not be sufficient in these patients. Anti- all cases of PACS routinely. However, if there is a situation
glaucoma drugs can be used to lower IOP, but a definitive where risk of developing acute angle closure is high or the
therapy would be required depending on the cause of the impact of acute angle closure on patient’s quality of life
angle closure. is likely to be severe, LPI should be offered even at PACS
stage. I do LPI at PACS stage in one-eyed patients, the fellow
Dr. Sirisha Senthil: Young patients with PACG may eye having acute angle closure episode, patients requiring
have anatomical abnormalities with regards to ciliary body repeated dilatation of the pupil (e.g. diabetic retinopathy),
position, lens position or narrow/ short anterior and or patients with family history of blindness due to angle closure
posterior segments. The conditions like plateau iris syndrome, glaucoma and patients living in remote areas or when access
nanophthalmos and spherophakia need to be considered to medical care is not available easily.
as differentials also. After ruling out posterior segment
pathology, do specular counts, rarely ICE can present with Dr. Sirisha Senthil: Response: Indications for YAG PI
features of angle closure and can be bilateral. Need to rule in PACS are:
out viral etiology. Other ocular conditionsthat can coexist
or areassociated with PACG in young are posterior segment - Occludable angles with moderate pressure for
pathology like retinitis pigmentosaor retinoschisis. There indentation.
eyes have typical features of angle closure, very shallow
anterior chamber, normal axial lengths remain progressive - Symptomatic PACS with headache and eye pain.
despite peripheral iridotomy and most often need surgery.
Trabeculectomy in these eyes is difficult and have significant - PACS with small discs at risk of ischemic
post-operative complications. neuropathy/ vascular occlusions.

12 DOS Times - Volume 25, Number 3, November-December 2019 www.dosonline.org/dos-times

Focus

- Other eye of patients with PAC/PACG – Patients Pilocarpine may not be effective in increasing aqueous
unlikely to come back for follow-up with positive family outflow in eyes with complete synechial angle closure.
history of PACG. Pilocarpine has no role in phakic eyes with angle closure
glaucoma.
Dr. Shamira Parera: The recent ZAAP study, examined
the natural history of PACS and the potential advantages Dr. Surinder Singh Pandav: We generally do not use
of LPI. The rate of developing raised IOP, PAS or APAC pilocarpine in PACG after laser iridotomy due to its side
was much lower than we expected in PACS: less than 1% effects. All other antiglaucoma drugs can be used to lower
per year. LPI eyes had almost 50% reduction in the risk of IOP in these eyes. Prostaglandin analogues, beta-blockers,
developing PAC or APAC and was the laser procedure itself alfa-agonists and carbonic anhydrase inhibitors have been
was extremely safe. Hence, we tend to perform LPI less found to be efficacious in lowering IOP in angle closure
nowadays and prefer to educate the patient and monitor glaucoma and are preferred over pilocarpine. If other durgs
unless they need to be frequently dilated. are not available or not tolerated, pilocarpine can be used
even after laser iridotomy. Elderly patients, pseudophakic
Dr. Ronnie George: I perform YAG PI in fellow eyes and aphakic eyes tolerate pilocarpine well and is very useful
of persons who have had an acute angle closure crisis, those in lowering IOP sometime.
with a confirmed family history of glaucoma, eyes requiring
repeated pupillary dilatation or those with poor access to eye Dr. Sirisha Senthil: The indication for Pilocarpine post-
care. peripheral iridotomy is in eyes with plateau iris syndrome
(PIS). The benefits of Pilocarpine far outweigh the side
Dr. Dewang Angmo: Is there any role of effects. Side effects of pilocarpine like pupillary constriction
pilocarpine in PACG post iridotomy in todays age, and posterior synechiae formation make cataract surgery at a
knowing its side effects vis-a vis better classes of anti- later time point slightly difficult. The ciliary contraction with
glaucoma medications in hand? brow ache is a short-lived side effect which most patients (not
all) tolerate. The benefits are: preventsprogressive synechiae
Prof. Ramanjit Sihota: Pilocarpine does not produce angle closure thereby helps with better IOP control, prevents
significant browache etc. in adult eyes with brown irides progression of glaucoma, helps avoid surgery. None of the
after a few days. In PACG, it adds to the effect of other other classes of antiglaucoma medications including the
medications by at least 15%. current newer ones can help with these mechanisms in PIS.

Dr. S.R. Krishnadas: Long term pilocarpine treatment Dr. Shamira Parera: Generally, pilocarpine has
in phakic eyes, even post iridotomy can cause chronic miotic been superseded by better drugs, especially prostaglandin
induced angle closure by progressive synechial angle closure analogues. Whilst the well-known side effects are milder
and can actually worsen control of intraocular pressure in the older population and it is inexpensive, it has been
over time. Ciliary muscle contraction caused by pilocarpine, relegated down the list of drugs to treat high IOP.
though can open and widen trabecular spaces reducing
resistance to aqueous outflow in quadrants of the angle that Dr. Ronnie George: Pilocarpine still has a role in PACG
is open, it also causes forward shift of the crystalline lens especially in cases of plateau iris where it may be beneficial
due to relaxation of zonules. Recurrent anterior shift in lens- in opening the angle even at low frequency of dosing (once
iris diaphragm causes chronic angle closure. Any residual or twice daily).
glaucoma Post LPI is also due to synechial closure in PACG.

www.dosonline.org/dos-times DOS Times - Volume 25, Number 3, November-December 2019 13

What’s New

Corneal Neurotisation for
Neurotrophic Keratitis

1Deepali Singhal MD, 2Prafulla K. Maharana MD
1. Clinical Rsearch fellow in Refractive Surgery, Institute of Vision and Optics, University of Crete, Greece,
2. Dr. R.P. Centre for Ophthalmic Sciences, AIIMS, New Delhi, India.

Neurotrophic keratitis is a degenerative cornea wolkow et al. Direct approach: This technique involves
disease of the cornea associated with transposing and re-routing a donor
impairment of corneal sensation, Mechanism sensory nerve to the cornea.
leading to a delayed epithelial healing. Themechanismleadingtoreinnervation
The hallmark of this condition is is not completely understood. After Indirect approach: This technique uses an
the defect in trigeminal corneal any peripheral nerve transection, autologous or allogenic nerve graft as a
innervation, which may occur due to Wallerian degeneration occurs, during link between the anesthetic cornea and
lesion at different levels of this nerve which a microenvironment is created the donor sensory nerve.
pathway1. that allows successful regrowth of the
This condition makes the cornea more proximal nerve segment. Schwann Results
susceptible to trauma and reduced reflex cells express surface molecules that Various published case series
tearing associated with delayed healing, guide regenerating fibres. The nerve demonstrate an objective improvement
which further increase the chances of graft provides adequate Schwann in corneal sensation and corneal
corneal ulceration and stromal melt if cells and endoneurial support to epithelial healing. Moreover, In vivo
not treated appropriately2. allow the regeneration process to take confocal microscopy has shown
Various treatment modalities described place. The regeneration of corneal growth of corneal nerves following the
so far are aimed at improving the axons after surgical procedures such procedure. Wolkow24. Various animal
ocular surface environment and are as photorefractive keratectomy and studies have revealed that corneal
thus, passive in nature. No modality laser in situ keratomileusis has been neurotization resulted in nerve growth
addresses the actual pathophysiological previously demonstrated Weis et al5,6. through the graft and that the new
cause. Corneal neurotisation is the nerves in the cornea are derived from
only therapeutic modality, which History the donor sensory nerve and not from
can address the underlying cause Modern corneal neurotization was pre-existing corneal nerves Wolkow25.
by stimulating the regeneration first described 10 years back in 2009.
of trigeminal nerve fibres. Topical Wolkow et al5. An earlier but more Corneal neurotisation has been
treatment with various neurotrophic complicated approach was described reported to be performed in 32 patients
factors like insulin growth factor-1 and in the neurosurgical literature by Samii till 2019. The median duration from loss
substance P have been described and in 1972 and 1981, but it did not gain of sensation to corneal neurotization
has shown promising results in such importance due to the complexity of was 3.35 years. Most common cause
cases Weis et al1,4. the procedure and its limited benefits. of loss of corneal sensation was direct
Neurotisation involves the transfer of Wolkow6. physical injury to the nerve [23 (72%)]
a healthy nerve as a donor of neurons Terzis et al in 2009; described a direct with prior herpes zoster being reported
and their axons to reinnervate distal supraorbital and supratrochlear nerve in 5, 17% patients only. 31/32 patients
targets that have lost motor or sensory transfer via a bicoronal incision, thus showed improvement in sensation
function. Corneal neurotization is avoiding craniotomy as compared to postoperatively, out of which 1 lost
an innovative surgical approach for the previos technique. wolkows et al5. that improvement 15 months later.
restoring corneal sensation, whereby 23/32, 71.8% patients also documented
the sensory functions of a normal donor Techniques improvement in visual acuity. The
nerve are rerouted to an anesthetic Two surgical approaches have been median time to objective return of
described; direct and indirect (Table 1). corneal sensation was 0.5 years wolkow
et al.

14 DOS Times - Volume 25, Number 3, November-December 2019 www.dosonline.org/dos-times

What’s New

Table 1: Approaches to Corneal Neurotisation [Wolkow 2019]

Direct Approaches

Author, year Procedure name Steps Advantages Disadvantages Outcome
Large bi-coronal 6/6 patients
Terzis et al, Bicoronal incision A bicoronal incision Avoids incision, prolonged showed
2009 5 with contralateral across the scalp- transcranial surgical time, risk of improved
supraorbital or supraorbital and approach, alopecia
corneal
supratrochlear nerve supratrochlear interpositional sensation
transfer nerve bundles graft and second and visual
contralateral to the surgical site acuity at 2.8
anesthetic cornea to 16 years
are identified and follow-up.
dissected- the nerve
bundles are reflected
down and tunneled
subcutaneously across
the nose to an eyelid
crease incision and
then directed toward
the globe into the sub-
Tenon space.

Jacinto et al, Hemicoronal incision A hemi-coronal - Smaller Prolonged surgical Improved
2016 12 with ipsilateral scalp incision with a incision - Avoids time, risk of alopecia corneal
supraorbital or subgaleal dissection interpositional sensation
supratrochlear nerve above the orbital rim- graft and second and corneal
transfer three branches of the surgical site function and
supraorbital nerve return of
were transected 6 cm normal scalp
from the supraorbital sensation at 8
notch and tunneled months
into an ipsilateral lid
crease incision- then
directed through a
blepharotomy incision
into the superior
conjunctival fornix
into the sub- Tenon’s
space 360-degrees
around the corneal
limbus.

Leyngold et al, Endoscopic approach - Cosmetically - Endoscopic brow Improved
2018 15 with ipsilateral acceptable lift equipment corneal
or contralateral - Avoids required, can be sensation
supraorbital or interpositional used for ipsilateral and corneal
supratrochlear nerve graft and second or contralateral function at 3
transfer surgical site reinnervation months

2016 13 Inferior fornix - Cosmetically Greater morbidity Not available
transconjunctival acceptable than supraorbital or
incision with - Avoids supratrochlear nerve
ipsilateral interpositional donor (resulting
infraorbital nerve graft and second numbness of upper
transfer surgical site -No lip, cheek, teeth)
need for special
equipment

www.dosonline.org/dos-times DOS Times - Volume 25, Number 3, November-December 2019 15

What’s New

Direct Approaches

Author, year Procedure name Steps Advantages Disadvantages Outcome

Indirect Approaches

Jowett and Transcranial approach The globe is not -Craniotomy 2/2 patients
Pineda et al, 22 with greater occipital manipulated -Sural required
showed
nerve donor and sural nerve graft required improved
nerve interpositional (second surgical site) sensation at
autograft linking to - Isolation of occipital 3 months
proximal ophthalmic nerve required
nerve - Published outcomes 3/3 patients
with poor success showed
improved
Elbaz et al, Eyelid crease incision Cosmetically acceptable - Leg incision sensation at
2014 17, with supraorbital or incision for sural nerve 3 months
supratrochlear nerve autograft required 11/11
donor and sural nerve - A second patients
interpositional graft surgical team showed
may be needed for improment
autograft harvest,
longer operative
time
- nerve has to
regrow through
two surgical
junctions

Malhotra et The nerve fascicles Autograft harvest site - Neck incision Corneal
al, 13 were inserted into and nerve donor site require to harvest sensation
corneoscleral tunnels can be in one surgical greater auricular improved
Benkhatar et instead of being field nerve graft
slightly after
al, 21 sutured and were kept - A second 9 months
in place with fibrin surgical team
sealant tissue glue may be needed for 7/7 patients
autograft harvest, showed
Eyelid crease incision longer operative improved
with supraorbital time sensation at
or supratrochlear - nerve has to 3 months
nerve donor and regrow through
greater auricular two surgical
nerve interpositional junctions
autograft

Leyngold et al, Acellular nerve -Minimally invasive - - Cost of nerve
2018 23 allograft to ipsilateral Cosmetically acceptable allograft -
or contralateral
supratrochlear, - Shorter time Theoretical
supraorbital or
infraorbital nerve - Second surgical team inferiority of
not required allograft to
- Second incision
not required autologous

graft

16 DOS Times - Volume 25, Number 3, November-December 2019 www.dosonline.org/dos-times

What’s New

AxoGen’s Avance human acellular nerve 4. Yanai R, Nishida T, Chikama T-I, et al. ipsilateral frontal nerve: A novel surgical
graft has received an FDA designation Potential New Modes of Treatment of technique” [Am J Ophthalmol Case Rep
as a Regenerative Medicine Advanced Neurotrophic Keratopathy. Cornea. 4 2016 14-17]. Am J Ophthalmol Case
Therapy (RMAT) as an innova- tive 2015;34 Suppl 11:S121-127. Rep. 2016;4:87.
surgical solution for discontinuities in 14. Leyngold I, Weller C, Leyngold M, et
peripheral nerves wolkow27. 5. Wolkow N, Habib LA, Yoon MK, et al. Endoscopic Corneal Neurotization:
al. Corneal Neurotization: Review Cadaver Feasibility Study. Ophthal Plast
Complications of a New Surgical Approach and Its Reconstr Surg. 2018;34:213-216.
• Transient sensory deficit from the Developments. Semin Ophthalmol. 15. Malhotra R, Elalfy MS, Kannan R, et al.
2019;34:473-487. Update on corneal neurotisation. Br J
donor site. Ophthalmol. 2019;103:26-35.
• Post-operative deficits include 6. Stoll G, Müller HW. Nerve injury, axonal 16. Jowett N, Pineda Ii R. Corneal
degeneration and neural regeneration: neurotisation by great auricular nerve
numbness, pain and synesthesia. basic insights. Brain Pathol Zurich Switz. transfer and scleral-corneal tunnel
• Neuromas . 1999;9:313-325. incisions for neurotrophic keratopathy.
• Hypertrophic scars . Br J Ophthalmol. 2019;103:1235-1238.
• Long-term mild pain, cold 7. Kauffmann T, Bodanowitz S, Hesse 17. Elbaz U, Bains R, Zuker RM, et al.
L, et al. Corneal reinnervation after Restoration of corneal sensation with
sensitivity and minimal discomfort photorefractive keratectomy and laser regional nerve transfers and nerve grafts:
at the donor site. in situ keratomileusis: an in vivo study a new approach to a difficult problem.
Limitations with a confocal videomicroscope. Ger J JAMA Ophthalmol. 2014;132:1289-1295.
• An extensive surgery needing a Ophthalmol. 1996;5:508-512. 18. Benkhatar H, Levy O, Goemaere I,
multi-disciplinary approach. et al. Corneal Neurotization With a
• High cost and long duration of 8. Terzis JK, Dryer MM, Bodner BI. Great Auricular Nerve Graft: Effective
surgery. Corneal neurotization: a novel solution Reinnervation Demonstrated by In
• Long-term follow-up required. to neurotrophic keratopathy. Plast Vivo Confocal Microscopy. Cornea.
To conclude, neurotization is a budding Reconstr Surg. 2009;123:112-120. 2018;37:647-650.
revolutionary technique that shows 19. Leyngold IM, Yen MT, Tian J, et
promise of cure for neurotrophic 9. Samii M, Jannetta P, eds. The al. Minimally Invasive Corneal
corneas, but at this stage, it is still Cranial Nerves: Anatomy Pathology Neurotization With Acellular Nerve
reasonably invasive and still reserved Pathophysiology Diagnosis Treatment. Allograft: Surgical Technique and
for selected patients. Several surgical Berlin Heidelberg: Springer - Verlag; Clinical Outcomes. Ophthal Plast
approaches have been recommended 1981. Reconstr Surg. 2019;35:133-140.
and all have demonstrated success in
restoring corneal sensation in patients. 10. Fung SSM, Catapano J, Elbaz U, et al. Corresponding Author:
It is yet unclear whether one surgical In Vivo Confocal Microscopy Reveals
approach is superior to another. Corneal Reinnervation After Treatment Dr. Deepali Singhal
of Neurotrophic Keratopathy With Clinical Rsearch fellow in Refractive Surgery,
References Corneal Neurotization. Cornea. Institute of Vision and Optics, University of
1. Bonini S, Rama P, Olzi D, et al. 2018;37:109-112. Crete, Greece, India

Neurotrophic keratitis. Eye Lond 11. Catapano J, Antonyshyn K, Zhang JJ, et al.
Engl. 2003;17:989-995. doi:10.1038/ Corneal Neurotization Improves Ocular
sj.eye.6700616. Surface Health in a Novel Rat Model of
2. Weis E, Rubinov A, Al-Ghoul AR, et Neurotrophic Keratopathy and Corneal
al. Sural nerve graft for neurotrophic Neurotization. Invest Ophthalmol Vis
keratitis: early results. Can J Ophthalmol Sci. 2018;59:4345-4354.
J Can Ophtalmol. 2018;53:24-29.
3. Nishida T, Yanai R. Advances in 12. Inc A. Avance® Nerve Graft Receives
treatment for neurotrophic keratopathy. Regenerative Medicine Advanced
Curr Opin Ophthalmol. 2009;20:276- Therapy (RMAT) Designation. Globe
281. Newswire News Room. Regenerative-
Medicine-Advanced - Therapy - RMAT -
Designation.html. Published October 29,
2018. Accessed March 4, 2020.

13. Jacinto F, Espana E, Padilla M, et al.
Corrigendum to “Ipsilateral supraorbital
nerve transfer in a case of recalcitrant
neurotrophic keratopathy with an intact

www.dosonline.org/dos-times DOS Times - Volume 25, Number 3, November-December 2019 17

What’s New

Ripasudil in Glaucoma
Management

Dewang Angmo1 MD, DNB, FRCS, FICO, MNAMS, Barkha Gupta1 MD, Neha Midha2 MD
1. Dr. R.P.Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
2. Advanced Eye Care and Glaucoma Services, New Delhi, India.

Abstract: Ripasudil is a highly selective and potent Rho-associated coiled/coil-containing kinase protein (ROCK) inhibitor. It lowers
intraocular pressure by decreasing smooth muscle contractile tone and extracellular matrix deposition in trabecular meshwork (TM),
resulting in widening of juxtacanalicular spaces thus enhancing conventional trabecular outflow. Ripasudil hydrochloride hydrate is 0.4%
solution and twice daily dosing is recommended. The maximum reduction of IOP occurs after 1 to 2 hours. Conjunctival hyperemia is the
most common adverse effect.

The Rho kinase inhibitors represent filamentous actin leading to glaucoma (POAG, Pseudoexfoliation
a new class of glaucoma medications relaxation of smooth muscle glaucoma) and ocular hypertension
that inhibit the downstream pathway contractile tone and decreasing
of the Rho family of small G-proteins to extracellular matrix deposition Additional uses corneal
increase outflow from the conventional in trabecular meshwork (TM) • Fuchs endothelial
(trabecular) outflow pathway in the eye. resulting in widening of
juxtacanalicualr spaces, thus, dystrophy (FECD)
Ripasudil (K-115), is a specific Rho- decreasing outflow resistance and
associated coiled-coil containing enhancing conventional trabecular • Diabetic retinopathy (DR) and
protein kinase (ROCK) inhibitor, first outflow. diabetic macular edema (DME)
approved in Japan in September 2014 • Additional benefits
as world’s first glaucoma drug with this o Protect trabecular meshwork • Glaucoma filtration surgery as
mechanism. antifibroblastic
from oxidative stress
Drug: Ripasudil is available as o Improve optic nerve perfusion • Retinal vein occlusions
0.4% topical ophthalmic solution o Neuroprotective effect: Increase
of ripasudil hydrochloride hydrate Efficacy
under brand name of Glanatec (Kowa ganglion cell survival In phase 1, single instillation clinical
Pharmaceuticals) / Ripatec (Ajanta o Facilitate corneal endothelial trial for different concentrations of
Pharma Ltd) dispensed in a 5ml bottle ripasudil, maximum IOP lowering effect
(available in India). wound healing was noted at 1-2 hours of instillation3.
o Anti-scarring effect: Reduce bleb
Mechanism of action In phase 2 randomized clinical study
• Ripasudil is a highly selective and scarring in glaucoma surgery of ripasudil in POAG and ocular
Dosage: Ripasudil hydrochloride hypertension, 0.4% ripasudil was
potent Rho-associated coiled/coil- hydrate 0.4% twice daily dosing. selected to be optimal dose with
containing kinase protein (ROCK) maximum IOP reduction (4.5 mmHg)
inhibitor. Pharmacology: Ripasudil has high 2hours after instillation4.
• Rhokinase/ Rho-associated coiled- intraocular permeability and works
coil- forming protein kinase (ROCK) by decreasing intraocular pressure A prospective 52 week study of 0.4%
is a serine/threonine kinase which (IOP) in a dose-dependent manner and ripasudil in glaucoma patients (POAG,
increases actomyosin contraction increasing flow facility. The maximum OHT or exfoliation glaucoma) showed
in smooth muscle cells activated by reduction of IOP occurs after 1 to 2 an IOP lowering of -2.6 and -3.7 mmHg
GTP. hours. at trough and peak as monotherapy5.
• ROCK inhibitors depolymerize
Indications: Medical management of A 2year, post marketing surveillance
study (ROCK- J), evaluated safety and
IOP lowering effect of 0.4% ripasudil in

18 DOS Times - Volume 25, Number 3, November-December 2019 www.dosonline.org/dos-times

What’s New

glaucoma/ OHT patients. They reported 1;79(10):1031-6. ophthalmologica. 2016 Feb;94(1):e26-34.
ripasudil as a safe and effective treatment 6. Tanihara H, Kakuda T, Sano T, Kanno
option for glaucoma management with 3. Tanihara H, Inoue T, Yamamoto T,
adverse drug reactions seen only in 8% Kuwayama Y, Abe H, Araie M. Phase 1 T, Imada R, Shingaki W, Gunji R. Safety
subjects, lower discontinuation rate and clinical trials of a and efficacy of ripasudil in Japanese
significant IOP reduction6. patients with glaucoma or ocular
selective Rho kinase inhibitor, K-115. hypertension: 3-month interim analysis
Adverse drug reactions JAMA ophthalmology. 2013 Oct of ROCK-J, a post-marketing surveillance
• Conjunctival hyperemia (74.6%- 1;131(10):1288-95. study. Advances in therapy. 2019 Feb
1;36(2):333-43.
most common side effect). 4. Tanihara H, Inoue T, Yamamoto
• Blepharitis (20.6%). T, Kuwayama Y, Abe H, Araie M, Corresponding Author:
• Allergic conjunctivitis (17.2%). K-115 Clinical Study Group. Phase 2
randomized clinical study of a Rho Dr. Dewang Angmo MD, DNB, FRCS,
References kinase inhibitor, K-115, in primary FICO, MNAMS
1. Dhillon J. Rhokinase Inhibitors novel open-angle glaucoma and ocular Dr. R.P.Centre for Ophthalmic Sciences,
hypertension. American journal of All India Institute of Medical Sciences,
Potential Treatment Modality for ophthalmology. 2013 Oct 1;156(4):731-6. New Delhi, India
Glaucoma. The Official Scientific Journal
of Delhi Ophthalmological Society. 2016 5. Tanihara H, Inoue T, Yamamoto T,
Mar 10;26(4):272-4. Kuwayama Y, Abe H, Fukushima A,
2. Schehlein EM, Robin AL. Rho-associated Suganami H, Araie M, K 115 Clinical
kinase inhibitors: evolving strategies Study Group, Uchino M, Iwasaki M. One
in glaucoma treatment. Drugs. 2019 Jul year clinical evaluation of 0.4% ripasudil
(K 115) in patients with open angle
glaucoma and ocular hypertension. Acta

www.dosonline.org/dos-times DOS Times - Volume 25, Number 3, November-December 2019 19

Subspeciality-Cornea

Corneal Collagen Cross-Linking

Mohamed Ibrahime Asif MD, Prafulla K. Maharana MD, Namrata Sharma MD
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.

In 1993, Professor Theo Seiler from aOn2:io(n1,) singlet tOri2ggaenrds (2) superoxide failed to demonstrate significant long-
university eye hospital in Dresden first which the formation term increase in corneal hysteresis and
performed CXL and found a significant of crosslinks that stabilize the cornea corneal resistance factor6.
increase in corneal biomechanical during CXL3.
property of the cornea. They found Indications
out the absorption spectrum of In general, one can discuss two principal 1. Primary indication for the use of
riboflavin containing cornea were pathways:
365-370 nm and 460 nm, but there CXL is to arrest the progression of
were no LEDs available to generate • Type I reaction: Aerobic conditions keratoconus.
UV light. In December 2005, the first (with oxygen) occur within the first 2. Other indications include pellucid
commercially available CXL device and 10–15s of UV exposure, followed by marginal degeneration, iatrogenic
riboflavin were delivered by Peschke the depletion of O2.
ectasia resulting from LASIK, PRK
and IROC. Its clinical usefulness for and radial keratotomy
halting the progression of KC was first • Type II reaction: The photosensitizer 3. CXL has been used in combination
demonstrated by Wollensak et al1. in (riboflavin) interacts with the with other treatments like
2003. Irradiation of 30 min was very surrounding molecules by hydrogen intracorneal ring segment
time consuming and shorter treatment transfer, resulting in the formation implantation and limited
time with higher irradiation was of crosslinks and producing O2 topography-guided ablation
proposed by Avedro (KXLTM System), molecules and hydrogen peroxide. 4. It has been used as short palliative
and thus, other CXL systems were Sensitizer riboflavin reacts with treatment in patients with
delivered with higher irradiances and UV, converting singlet oxygen pseudophakic bullous keratopathy
therefore the second generation of CXL into hydrogen peroxide, resulting 5. Because of potential antimicrobial
devices was developed. Recently, the hinydardoegpenletpioernoxoifdOe2e. fIfnecrtetisurknn,otwhins properties, promising outcomes
U.S. Food and Drug Administration to cause crosslinks.
have been reported in the treatment
(FDA) approved in April 2016 to of bacterial, fungal, protozoal and
AvedroTM Inc.’s CXL system to treat Another characteristic of reduced atypical keratitis
patients with progressive KC and post- riboflavin is that it does not absorb
LASIK ectasia. Hafezi/ Seiler found UV light at 370 nm as the riboflavin Contraindications
a method to swell thin corneas with molecule itself. Therefore, adding 1. Age< 8 years
hypo-osmolar riboflavin solution2. more UV-light photons will not create 2. Pregnant/ nursing mothers.
more activated riboflavin, if most of 3. Central corneal scarring.
Mechanism of Action the molecules are in the reduced state. 4. Severe ocular surface disease.
The photosensitizer riboflavin is The biomechanical stiffening was one 5. Collagen vascular diseases.
a hydrophilic molecule, creating a of the effects of the CXL procedure. 6. Severe immunosuppression.
pivotal role in the CXL process as it Other effects of CXL were a higher 7. Riboflavin allergy.
absorbs the UV photons effectively, and resistance against enzymatic digestion 8. PACK-CXL avoided in herpes
then the exited riboflavin molecules or reduced biodegradation, a reduction
can transfer the energy to surrounding of corneal swelling, a higher shrinking keratitis, infiltrates deeper than 250
reaction partners such as oxygen or temperature, and a larger collagen fiber microns, descematocele, perforated
other molecules. Riboflavin absorbs diameter. It has been reported that a ulcer.
UV light up to 95% thought the 450% increase in Young’s modulus
stromal thickness and is the preferred and a 328.9% increase in rigidity can Technique
photo-initiator of the active forms of occur following CXL4,5. However, Epi-OFF technique: The original Dresden
recent studies using the ORA have

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Subspeciality-Cornea

protocol required epithelial abrasion 2. Mechanical modification of CXL10. They showed empirically,
to allow sufficient penetration of epithelial permeability the critical role of oxygen species
the riboflavin molecules (Epi-OFF • Incomplete abrasion, superficial through experiments that revealed the
technique). The original Dresden removal of epithelial cells with inhibition of CXL in the presence of
protocol used an energy dose of 5.6 laser sodium azide and the enhancement of
J/cm2 with an intensity of 3 mW/ • A destructive device to create it in the presence of deuterium oxide
cm2 for an exposure time of 30 min. pockmarks in the epithelium (D2O).
Advantages of the epi-off method are (epithelium disrupter) (maintain Contact lens assisted CXL: Jacob and
the fast penetration of riboflavin into much epithelium but also Agarwal11,12 have pointed out that
the stroma and a high concentration promote riboflavin penetration) patients with thin corneas (thinner
of riboflavin in the stroma, therefore a • Superficial scratches
than 400μm) cannot safely undergo
strong and deep CXL effect and, by the conventional CXL because the CXL
high absorption of the UV light, a strong 3. Iontophoresis8 reaction may take place at or near the
protection of the endothelium, lens, 4. Intrastromal application: needles; endothelium. To remedy this, they
and retina. Disadvantages are the pain, used a riboflavin-soaked, UV barrier-
discomfort in the form of burning and pocket-application9 (using the free contact lens to create a precorneal
tearing for many days, delay in contact IntraLase femtosecond laser to riboflavin film in order to decrease the
lens wear, and the risk of infections. create a corneal pocket at 100micron UV irradiance.
depth and then instilling 0.1% Alternative agents
Accelerated CXL: Epithelium-off with 15 riboflavin one time in that pocket) Cherfan et al. have developed an
min RF + UVA: 9 min x 10 mW/cm2 or 5. Vacuum mediated delivery- a alternative CXL technology that uses
5 min x 18 mW/ cm2 or 15 min x 6mW/ vacuum chamber is placed on top green light to activate Rose Bengal
cm2 (product of two numbers remains of the patient’s intact cornea and (RB), a well-known diagnostic agent
90).
then filled with a small reservoir of for ocular surface damage13. They have
riboflavin. Vacuum is then applied demonstrated that light-activated
Total energy dose: 5.4 J/cm2
over the reservoir, with an airtight RB can be used to seal wounds in the
seal forming at the base plate. The cornea, to bond amniotic membrane to
Based on Bunsen - Roscoe law of negative pressure built up within the corneal surface, and for applications
reciprocity(theeffectofaphotochemical the space overlying the cornea, and in many other tissues. RGX significantly
reaction is directly proportional to total riboflavin has the counterintuitive increases corneal stiffness in a rapid
irradiation dose irrespective of time)
- effect of drawing riboflavin into treatment (12 min total time), does not
Less surgical time, increased patient the corneal stroma across an intact cause toxicity to keratocytes, and may
comfort with comparable results as epithelium. be used to stiffen corneas thinner than
proven by a randomized controlled Also the riboflavin must be modified for 400μm.
trial7. Conjectured that compliance is transepithelial application as follows: PACK-CXL-Photo-activatedChromophore
better, especially in children
Avedro for keratitis - CXL: PACK-CXL was
KXLTM System (Avedro, Waltham, • Without dextran
performed according to the Dresden
Mass., USA) uses this protocol. CXL protocol for KC, with the following
• Hypo-osmolar solution (NaCl modifications: First, the beam is either
Epi-on CXL- The advantages of the concentration < 0.44%) focused on the lesion or includes the
epi-on method are less pain, more lesion. In the case of a peripheral lesion,
comfort during the early postoperative • Higher riboflavin concentration the surgeon might need to expose the
period, faster visual recovery, lower (0.2% to 0.5%). limbus. Second, manually remove the
risk of infection, and faster return to epithelium surrounding the infiltrate
contact lens wear. Several approaches Because the riboflavin diffusion is over a few millimeters to allow complete
to increase the permeability of the concentration- and time-dependent, penetration of the riboflavin around
epithelium to riboflavin are suggested: a higher concentration of riboflavin the lesion. Usually, this is combined
solution (0.2% to 0.5%) gives higher with the corneal scraping. Fluorescein
1. Pharmacologic modification of concentrations in the stroma. is competing with riboflavin for UVA
epithelial permeability absorption thus reducing the overall
Customized Debridement: Epithelial antiseptic effect of the surgery and
Benzalkonium chloride (BAC), Island CXL - Cone apex region is should be avoided immediate prior to
ethylenediamine-tetraacetic acid left intact (epithelial island) with
(EDTA), chlorobutanol, channel- selective epithelial debridement of the
forming peptide (NC-1059), antibiotic paracentral region (ep-off island)


gentamicin, proparacaine, tetracaine, Dus2eO:oMf DcC2Oallaest al. have reported on the
ethanol. a method of enhancing

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Subspeciality-Cornea

CXL14. Endothelial Damage Journal of Cataract & Refractive Surgery.
2003 Sep 1;29(9):1780-5.
Description The threshold for endothelial damage
Molecular effect UV light: direct has been shown to be 0.35 mW/cm2, 5. Cartwright NE, Tyrer JR, Marshall J. In
damage through cross-links creation which is approximately twice compared vitro quantification of the stiffening
between nucleic acids in DNA/RNA.
with 0.18 mW/cm2 that reaches the effect of corneal cross-linking in the
Photo-activated riboflavin: ROS interact corneal endothelium with the currently human cornea using radial shearing
with nucleic acids and cell membrane. recommended protocol. This may be speckle pattern interferometry.
Macroscopic effect Increased resistance due to a stromal thickness of less than Journal of Refractive Surgery. 2012 Jul
to enzymatic digestion. 400μm or incorrect focusing. 1;28(7):503-7.
Transitory increased hypopyon.
Reduced pain postoperatively. Treatment Failure 6. Greenstein SA, Fry KL, Hersh PS. In vivo
PACK - CXL leads to faster re- biomechanical changes after corneal
epithelialization more in gram-positive CXL failure is defined as keratoconic collagen cross-linking for keratoconus
bacteria, followed by gram-negative progression following treatment. The and corneal ectasia: 1-year analysis of a
bacteria, acanthamoeba, and fungi15. It incidence has been reported to be 7.6% randomized, controlled, clinical trial.
seems to be most effective in blocking at one-year follow up. Various risk Cornea. 2012 Jan 1;31(1):21-5.
corneal melting caused by gram- factors for CXL failure include the age of
negative bacteria, followed by gram- 35y or older, spectacle-corrected visual 7. Hashemian H, Jabbarvand M,
positive bacteria, Acanthamoeba and acuity better than 20/25, a maximum Khodaparast M, Ameli K. Evaluation
finally fungi1,16. Best results of BCVA keratometry reading greater than 58.00 of corneal changes after conventional
were reported in infections with D and cornea thickness <400μm. versus accelerated corneal cross-
Moraxella and Staphylococcus aureus. linking: a randomized controlled trial.
Conclusion Journal of Refractive Surgery. 2014 Dec
Complications CXL with riboflavin and UVA irradiation 1;30(12):837-42.
Postoperative infectious keratitis is a minimally invasive technique
The main risk factors include the that modifies corneal stroma and 8. Vinciguerra R, Spoerl E, Romano MR,
presence of an epithelial defect, use of increases the biomechanical stability. Rosetta P, Vinciguerra P. Comparative
soft bandage contact lens, and topical It is still an evolving technology and stress strain measurements of human
corticosteroids in the immediate has the potential to maximize visual corneas after transepithelial UV-A
postoperative period. In cases of corneal rehabilitation with various upcoming induced cross-linking: impregnation
infection after CXL, contact with the modifications in the technique. with iontophoresis, different riboflavin
infectious agent likely occurred during solutions and irradiance power.
the early postoperative period rather References Investigative Ophthalmology & Visual
than during surgery because CXL not 1. Wollensak G, Spoerl E, Seiler T. Science. 2012 Mar 26;53(14):1518-.
only damages keratocytes, but it also
kills bacteria and fungi. Riboflavin/ultraviolet-A-induced 9. Alió JL, Toffaha BT, Piñero DP,
Corneal Haze collagen crosslinking for the treatment Klonowski P, Javaloy J. Cross-linking
The incidence of post-CXL stromal haze of keratoconus. American journal of in progressive keratoconus using an
has been reported to be 9% at one year ophthalmology. 2003 May 1;135(5):620- epithelial debridement or intrastromal
follow up. This is most commonly seen 7. pocket technique after previous
in cases of advanced keratoconus and 2. Hafezi F, Mrochen M, Iseli HP, Seiler T. corneal ring segment implantation.
mainly involves the anterior stroma Collagen crosslinking with ultraviolet-A Journal of Refractive Surgery. 2011 Oct
up to a depth of around 60% that is and hypoosmolar riboflavin solution 1;27(10):737-43.
300μm. Various factors contributing in thin corneas. Journal of Cataract &
to the development of haze include Refractive Surgery. 2009 Apr 1;35(4):621- 10. McCall AS, Kraft S, Edelhauser HF,
repopulation of activated keratocytes, 4. Kidder GW, Lundquist RR, Bradshaw
stromal swelling pressure changes, 3. Richoz O, Hammer A, Tabibian HE, Dedeic Z, Dionne MJ, Clement EM,
Proteoglycan-collagen interactions, and D, Gatzioufas Z, Hafezi F. The Conrad GW. Mechanisms of corneal
glycosaminoglycan hydration. biomechanical effect of corneal collagen tissue cross-linking in response to
cross-linking (CXL) with riboflavin and treatment with topical riboflavin and
UV-A is oxygen dependent. Translational long-wavelength ultraviolet radiation
vision science & technology. 2013 Nov (UVA). Investigative ophthalmology &
1;2(7):6-. visual science. 2010 Jan 1;51(1):129-38.
4. Wollensak G, Spoerl E, Seiler T. Stress-
strain measurements of human and 11. Wollensak G, Aurich H, Wirbelauer C,
porcine corneas after riboflavin- Sel S. Significance of the riboflavin film
ultraviolet-A-induced cross-linking. in corneal collagen crosslinking. Journal
of Cataract & Refractive Surgery. 2010
Jan 1;36(1):114-20.

12. Jacob S, Kumar DA, Agarwal A, Basu
S, Sinha P, Agarwal A. Contact lens-
assisted collagen cross-linking (CACXL):
a new technique for cross-linking thin
corneas. Journal of Refractive Surgery.

22 DOS Times - Volume 25, Number 3, November-December 2019 www.dosonline.org/dos-times

Subspeciality-Cornea

2014 Jun 1;30(6):366-72. 15. Price MO, Tenkman LR, Schrier A, Corresponding Author:
Fairchild KM, Trokel SL, Price FW.
13. Cherfan D, Verter EE, Melki S, Gisel TE, Photoactivated riboflavin treatment of Dr. Prafulla Kumar Maharana
Doyle FJ, Scarcelli G, Yun SH, Redmond infectious keratitis using collagen cross- Dr. Rajendra Prasad Centre for Ophthalmic
RW, Kochevar IE. Collagen cross-linking linking technology. Journal of refractive Sciences, All India Institute of Medical Sciences,
using rose bengal and green light to surgery. 2012 Oct 1;28(10):706-13. New Delhi, India.
increase corneal stiffness. Investigative
ophthalmology & visual science. 2013 16. Khan YA, Kashiwabuchi RT, Martins
May 1;54(5):3426-33. SA, Castro-Combs JM, Kalyani S, Stanley
P, Flikier D, Behrens A. Riboflavin and
14. Richoz O, Gatzioufas Z, Francois ultraviolet light a therapy as an adjuvant
P, Schrenzel J, Hafezi F. Impact of treatment for medically refractive
fluorescein on the antimicrobial Acanthamoeba keratitis: report of
efficacy of photoactivated riboflavin 3 cases. Ophthalmology. 2011 Feb
in corneal collagen cross-linking. 1;118(2):324-31.
Journal of Refractive Surgery. 2013 Dec
1;29(12):842-5.

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Subspeciality-Cataract

Trifocal Intra-ocular Lenses:
Overview

Ritika Mukhija MD, M. Vanathi, MD
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.

With advancement in surgical diffractive, refractive–diffractive and in the range of +10.0 to +35.0 D (0.5 D
techniques and intra-ocular lens accommodating. increments).
design, cataract surgery has gradually It was in 2010, that the first trifocal
evolved into a refractive procedure. IOL, FineVision was introduced by a AT LISA
Spectacle independence, not just company Physiol (Belgium), based on a The AT LISA tri 839MP is a single-piece,
for distance, but also for near and proprietary diffractive profile3. This was UV filtering, refractive–diffractive
intermediate vision, is now one of the followed by introduction of another trifocal preloaded IOL. It is composed of a
post-operative expectations of many trifocal IOL (AT LISA tri 839MP) by Carl hydrophilic-acrylic (25% water content)
patients. Multifocal intra-ocular lenses Zeiss Meditec, based on a combined material with hydrophobic surface
(IOLs) were first introduced around refractive–diffractive principle. Lastly, properties5. It has a central trifocal area
three decades back with an aim to AcrySof IQ PanOptix, launched in (main zone) of 4.34-mm diameter and
correct presbyopia along with cataract. 2015 by Alcon Laboratories, is another a peripheral bifocal optic area (phase
They produce simultaneous images refractive–diffractive trifocal IOL, zone), offering a +3.33 D near addition
using either diffractive or refractive which is the first trifocal IOL to gain and +1.66 D intermediate addition, with
optics; in practice, most designs are FDA approval4. a reading and intermediate distance of
actually bifocal. Studies have reported 40 and 80 cm, respectively. There is a
significantly better near vision with FineVision slow transition area between the main
these IOLs; however, intermediate The FineVision Micro F (Fine: acronym zone and phase zones, referred to as a
vision, such as that needed while for “Far, Intermediate and Near”) is a diffraction structure, used to reduce the
working on computers, or using single-piece, four closed-loop haptics disturbing light phenomena including
tablets and smartphones, is often design, 25% hydrophilic acrylic, UV glare and halo and improve the overall
unsatisfactory1. Trifocal IOLs help in and blue light filtering, fully diffractive quality of retinal imaging and VA. It
solving this problem and aim to provide trifocal IOL. It works by combining transmits 85.7% of light energy to the
a full range of refractive correction 2 diffractive profiles and has an retina across all pupil sizes and has a
to the patient2. A brief overview of intended addition power of +1.75 D for light distribution of 50% for distance,
the optics and available designs, pre- intermediate vision and a maximum 20% for intermediate, and 30% for near
operative work-up, clinical outcomes addition power of +3.5 D for near vision. The IOL is available in spherical
and limitations are discussed below. vision offering an intermediate and powers from 0.0 to 32.0 D in 0.5-D
reading distance of 80 cm and 40 cm, increments.
Optics and Designs respectively. It transmits 86% of light
Multifocal IOLs work on the principle energy to the retina. The apodized IOL AcrysOf IQ PanOptix IOL
of simultaneous vision, where different optic is designed to allocate 49% of the The PanOptix Model TFNT00 is a
areas of the IOL are designed for light energy to distance vision, 34% to single-piece, UV and blue light filtering,
different focal planes, usually for near near vision, and 17% to intermediate hydrophobic- acrylic, non-apodized,
and distance vision, as in traditional vision, at a 3.0 mm pupil aperture. foldable trifocal IOL. It has a central
bifocal IOLs or for intermediate vision, Another similar trifocal diffractive IOL, biconvex optic, with an inner diffractive
as in trifocal IOLs. At any given time, FineVision HP (PhysIOL), launched in and an outer refractive zone and has 2
one image is focused on the retina, while 2017, is also available now; however, it open-loop haptics. The posterior lens
the second image is highly defocused is made of hydrophobic material. It is surface is spherical, and the anterior
with very little structure. There are a 1-piece, glistening-free lens available surface is aspheric with a diffractive
four main categories of multifocal IOLs surface on the central 4.5 mm portion of
currently available, including refractive, the optic zone, and divides the incoming

24 DOS Times - Volume 25, Number 3, November-December 2019 www.dosonline.org/dos-times

Subspeciality-Cataract

light to create an intermediate addition IOL implantation. monofocal IOLs, where an interval
power of +2.17 D (60 cm) and a +3.25 D • Visual needs of patient: These should of two weeks between two eyes
(40 cm) near add power. The anterior may be reasonable, a longer interval
surface is designed with negative be thoroughly assessed, including should be considered for these IOLs.
spherical aberration to compensate for the working distance and lighting This would allow enough time
the positive spherical aberration of the conditions for various tasks between surgeries on two eyes so
average human cornea. performed, and then correlated that the visual function of first eye
with objective measures of the can be accurately assessed.
The PanOptix IOL is based on a pupils under photopic, mesopic, • Patient counselling: Last but not the
quadrifocal (4 foci) design and uses and scotopic lighting levels. This least, it is important for the patient
a proprietary optical technology, would help not only to guide the to have realistic expectations after
ENLIGHTEN, to redistribute the focal selection of a specific IOL design, the surgery. complete spectacle
point at 120 cm to the distance focal but also reveal whether the optic independence should never be
point for amplified performance. This size of an accommodating IOL is offered by the surgeon, as even
results in 2-step heights that is equal to 2 adequate to avoid edge glare. under the best of circumstances
add powers/2 focal points (plus distance • Biometry: It is needless to say that patients may require spectacles for
from base curve; Figure 1). Light is split accurate IOL power measurement specific needs. This is often referred
to 3 foci (distance: ∞, intermediate at 60 and calculation is of utmost to as “Under-Promise and Over-
cm, and near at 40 cm). The 4.5 mm non- importance. Also, postoperative Deliver” in the corporate world.
apodized, diffractive zone allows high astigmatism greater than 0.75D
light utilization, transmitting 88% of may degrade the quality of Clinical Outcomes
light to the retina at a 3.0 mm pupil size, uncorrected vision, and should be Clinical outcomes across various
and provides optimized performance in dealt with accordingly (astigmatic studies have been relatively consistent,
a wide range of lighting conditions due keratotomy, multifocal toric IOLs, showing good unaided visual acuities
to low dependence on the pupil size9,10. etc.) for distance, intermediate and near
This light energy is distributed 25% • Ocular co-morbidities: Even with with the notable advantage over bifocal
each for near and intermediate and 50% advancement in designs, some IOLs noted at intermediate distances. A
for distance vision. It is available in a amount of optical compromise recent meta-analysis published in 2018
diopter (D) range of +6.0 to +30.0 D (0.5 occurs with these IOLs, hence they indicated that trifocal diffractive IOL
D increments) and +31.0 D to +34.0 D should be avoided in eyes with implantation is better than the bifocal
(1.0 D increments). pre-existing optical impairments, diffractive IOL in intermediate VA, and
such as maculopathy, amblyopia, provides similar or better in distance
Pre-operative Workup glaucoma with central visual field and near VAs without any major
Inadditiontotheroutinecomprehensive loss, or even in those predisposed deterioration in the visual quality.
workup done in any case planned for for the same.
cataract surgery with IOL, there are few • Ocular surface: Careful preoperative Marques et al compared the visual
principles that should be kept in mind assessment and treatment of outcomes after cataract surgery
when working up a patient for any aqueous tear deficiency and with bilateral implantation of either
presbyopia correcting IOL. meibomian gland disease is Finevision Micro F IOL or an AT Lisa
extremely important. If the tri 839 MP IOL and found that both
• Patient motivation: The patient quality of ocular surface cannot trifocal IOL models provided excellent
must be motivated enough to be improved to a reasonable level, distance, intermediate, and near
increase their range of daily a presbyopia IOL may not be a visual outcomes6. There was excellent
functions that can be performed suitable choice. predictability of the refractive results
without spectacle correction; those • Surgeon expertise: Premium IOLs, and optical performance were excellent,
who do not mind using glasses, may demand a high level of skills from and all patients achieved spectacle
not be good candidates. the surgeon; a well-centered and independence.
correctly sized capsulorrhexis,
• Patient personality: Although thorough cortical removal, and Carson D et al compared the optical
there are no specific guidelines, intact capsular bag are essentials in bench performance for PanOptix,
but a relatively positive, optimistic obtaining consistently good results FineVision, and AT LISA7. Contrast
and patient individual, who with these IOLs. sensitivity (CS) was evaluated with
understands that it may take • Staged implantation: Unlike modulation transfer function (MTF)
several months to adapt to the new sequential cataract surgery with measurements with 3 mean peaks
visual perception system, is more correspondingtodistance,intermediate,
likely to be suited for multifocal and near foci for all IOLs. PanOptix had

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Subspeciality-Cataract

Instrumentations and Devices for
Toric IOLs: Dillemmas and Choices

1N. Z. Farooqui MS, 2Kiran Bhanot MS, DNB
1.D.D.U. Hospital New Delhi, India
2. G.G.S.G. Hospital, New Delhi, India

Increased patient expectations about Javal Schiotz Keratometer IOL Master
the refractive outcomes after cataract
surgery have resulted in the increased Bausch and Lomb Keratometer Lenstar Ls 900
use of methods to correct astigmatism Manual Keratometer at 3.4 mm whereas Bausch & Lomb
during surgery. Approximately 30% of Early research suggested Manual Keratometry measures at 3.2 mm in the
all patient have corneal astigmatism of Keratometry as a Gold Standard. It central zone.
more than 0.75 D1. Two fundamental measures 2 points at 3-4 mm zone . Automated Keratometers:
reasons Toric IOL might not correct Javal Schiotz keratometery measures A) Iol Master; B) Lenstar
the refractive astigmatism are a) IOL Master (Carl Zeiss). It is an Optical
Magnitudinal error, b) Alignment error. Biometer based on partial coherence
Instrumentation and devices are interferometry (PCI) principle. The
instrumental in the efficacy of the Toric
IOL for: 1) Keratometry Measurement.
2) Pre-Operative Markings, 3) Intra-
Operative Alignment , 4) Post-Operative
Evaluation. Hence, it is crucial for
the Corneal Astigmatic assessment,
Target Axis Markings, Intra-operative
axis alignment of the Toric IOL to the
calculated toric axis to be accurate,
precise and reproducible.
Corneal Measurement can be done either
by Direct or Indirect method.
Direct Measurement: through reflected
light by the following Instruments.
Manual Keratometer:

A) Javal Schiotz ; B) Baush & Lomb
Automated Keratometer:

A) Iol Master; B) Lenstar Ls 900.
Placido Disk - Based Topographic Devices:
a) Atlas 9000 ; b) Keratograph
B. Indirect Measurements:

a) Orbscan S: b) Pentacam
c) Visante Omni System – Oct Based

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Subspeciality-Cataract

Figure 6 Figure 9 Figure 11

Figure 7 Figure 10 10) A tonometer marker is dipped
mm in length, nasal and temporal sides in an inkpad. It is positioned on the
Figure 8 are marked sequentially based on the Goldmann Tonometer at the slitlamp
may result in a relevant reduction in outer margin of the beam light focused and is used to touch the cornea.
astigmatism-reducing effect due to on corneal centre. Concerning the subjective clinical
the variable cyclotorsion when the Pendular-Marking Technique: (Figure 8) A applicability of the marking methods
patient changes to the supine position. pendular marker is dipped in an inkpad. the slit lamp and Bubble methods are
All marking procedure are performed The pendular marker uses a weight to easiest to handle. The Pendular marker
with the patient sitting and the head keep the marking fork of the instrument is more difficult to handle, because
straight as subjectively assessed by the in a horizontal position. The horizontal the extra weight of the device makes it
examiner; the patient is asked to fixate meridian is marked at the limbus. slightly harder to balance. Comparing
on a distant target at head height with Bubble - Marking Technique: (Figure the various techniques, the slit lamp-
the contralateral eye. The examiner 9). The eye is marked with Nuijts- marking technique showed the least
marks the right eye with the left hand Lane preoperative toric reference vertical deviation, and the pendular
and the left eye with the right hand. marker. The marker has a water-level marker showed the least rotational
Local anaesthetic eye drops are instilled bubble designed to aid in horizontal misalignment. The Tonometer Marker
before the cornea is marked. A lid positioning of the instrument. After, is less accurate and more difficult to use.
speculum is inserted to keep the eye the marker is dipped in a blue inkpad, The drawback of all the marking
open during the marking procedure. the limbus of the eye is touched to mark techniques is that it tended to produce
Direct Visual Marking Technique: The 2 points of the horizontal meridian and upward deviated marks. This is possibly
limitation of this method is that the inferior vertical meridian. due to marker in the patient’s field
the horizontal level is estimated by Tonometer - Marking Technique: (Figure to view which might cause him to
Surgeon’s experience only (Figure 6). squint or close the eyes. Thus , Bell’s
Slit-Lamp Marking Technique.: (Figure 7) phenomenon can be cause of the upward
The slit lamp is turned in the horizontal deviated marks. The ink diffuses, and
position. Next, a thin slit beam < 2.0mm smudges the markings. The irregular
is centered on corneal apex. Then, conjunctival – limbal surface could be
the horizontal meridian is marked a factor in problems associated with the
by sterile blue marker. However, the ink marking.
limitation is that the slit beam being 8 Wet - Field Osher Thermodot Marker:
(Figure 11) The wet field Osher
Thermodot Marker uses cautery to
create a tiny, indelible mark to identify
a chosen axis. Unlike ink, it can’t blur or
wash away.
Intra-Operative Marking and Alignment:
Manual Intra-Operative Markings:
A) Two hand axis marking technique:

(Figure 12) A marker and a guage
combo is used to mark the steep
meridian axis.
B) One hand axis marking technique:

30 DOS Times - Volume 25, Number 3, November-December 2019 www.dosonline.org/dos-times

Subspeciality-Cataract

Figure 12

Figure 14

Figure 13 Figure 16

(Figure 13) A marker and guage Figure 15 Figure 17
are built into a single instrument
to mark the steep meridian axis. Operating Microscope Slit Beam to giving continuous rapid snap shots.
Since the IOL is smaller than the Ascertain the Alignment of Toric IOL: 2) Holos Intraop (Clarity Medical System):
dimensions of these marks on the A sharp and bright slit light is projected It provides real time continuous
peripheral cornea, the surgeon simultaneously onto cornea & IOL. refractive data and assist in the
must interpolate these points When the Toric markings on the alignment of Toric IOL’s.
intraoperatively to estimate the anterior surface of the IOL coincides Advantage of Intra-Operative
final correct axis of alignment. with the violet markings on the cornea Wavefront Aberrometry9 is that
These markings are usually created is suggestive of perfect alignment of the it incorporates posterior corneal
with either a dye (e.g gentian violet) or IOL with the desired axis (Figure 14). astigmatism. It was found that 89.2% of
a surgical marking pen; both of which The Manual Marking Errors are related eyes post-operatively had astigmatism
often smudge or ‘bleed’, resulting in an to: i) Horizontal Axis Marking Error, of <0.50 D compared to 76.6% eyes
additional margin of error when the final ii) Alignment Axis Marking Error, iii) which did not use intraoperative
angle of alignment is approximated. Toric IOL Alignment Placement Error. aberrometry. It’s use avoids variability
Additionally, splinter haemorrhages This can amount to a mean total error in the corneal measurement and it
created by nicking the limbal palisades of 4.90 ± 2.10 ( 2.80 - 7.00 ). However, in generates best – fit refraction across
of Vogt likewise add an unnecessary individual cases, the error might be as the entire pupil axis. Also, it is a non-
margin of error. Furthermore, these high as 100 8. contact, non-invasive diagnostic
techniques focus on aligning the IOL Intra – Operative Aberrometers: for Intra - system, replacing the inherently
axis with the anatomic cornea and not Operative Assessment and Alignment imprecise marking method eliminating
the visual axis or the entrance pupil, Accurate astigmatism measurement misalignment due to cyclotorsion and
which is often not concentric with the and precise Toric IOL alignment can be smearing of the ink marks.
anatomical cornea5,6,7. done by intraoperative aberrometery. The main drawback is that it lengthens
The Aphakic Refractive measurements the operative time by about 5 minutes
Also, the axis position of the IOL must by the Aberrometer is used for and that the refractive surprises are
be interpolated between points on the calculation of Toric IOL power & Axis still encountered and the financial cost
peripheral cornea or limbus using a (Figure 15). aspect. Also, the larger astigmatism
straight instrument held above the 1) ORA-Verifeye (Alcon Surgicals): > 6.00 /7.00 D is not displayed. As it
plane of the cornea; depending on the Enables surgeons to confirm eye
anterior chamber depth and the depth stability prior to acquisition of data by
of focus of the operative microscope,
it is often not possible to keep the
instrument , lens marking, and limbus
in focus simultaneously.

www.dosonline.org/dos-times DOS Times - Volume 25, Number 3, November-December 2019 31

Subspeciality-Cataract

considers it as outlier measurement. Figure 18 and prevalence dat FOR CORNEl astigmatism
in 23,329 eyes. J Cataract Refract Surg
The factors that contribute to the Figure 19 2010;36:1479-1485.
variability to intraoperative wave front camera phone for slitlamp photography 2. Warren Hill, Rober Osher et al; Simulation of
aberrometry are; Eye Lid Speculum / (Figure 19) have been described8. Post- Toric IOL results: Manual keratometry versus
Eyelid squeezing; Stromal hydration operative photograph is imported in dual zone automated keratometry from an
and Variable SIA , all of which affect the the Adobe Photoshop (Version 7.0) and integrated biometer. J Cataract Refract Surg
refractive cylinder and axis. In addition by image analysis, axis of orientation of 2011;37:2181-2187.
the changes in intraocular pressure and the Toric IOL is determined. Wavefront 3. Hidenga Kobashi, Kazutak Kamiya, Akihito
ELP post-operatively, affect the IOL aberrometr is an objective method Igarashi et al . Comparison of corneal power,
power. to measure th IOL axis; however, corneal astigmatism, and axis location in
additional expensive equipment is normal eyes obtained from an autokeratometer
Integrated Cataract Suites: for Intra- required. and a corneal topographer. K Cataract Refract
Operative Assessment and Alignment Conclusion Surg 2012;38:648-654.
Keratometry based on reflection from 4. Alexandra Z. Crawford, Dipika V. Patek and
Integrated cataract suites are created tear layer such as Placido Topography Charles N.J. Comparison and Repeatability
by companies who have merged the may cause variability in measurements of Keratometric and Corneal Power
technologies to integrate and propagate use of artificail tear to alter the image Measurements Obtained by Orbscan II,
a surgical plan through seemless and 3-D tomographic devices may be a Pentacam, and Galilei Corneal Tomography
communication between devices, such good option in these cases. Both digital System. Am J Ophthalmol 2013;156:53-60.
as Alcon Surgicals (Lenstar, Verion, and manual marking methods showed 5. Sun X-Y, Vicary D, Montgomery P, Griffiths
Lensx, Luxor & ORA); Carl Zeiss Meditec high accuracy in aligning Toric IOLs M. Toric intraocular lenses for correcting
AG ( IOL Master, Callisto Eye, and OPMI intraoperatively11. Low magnitude astigmatism in 130 eyes. Ophthalmmology
Lumera); Bausch & Lomb (Cirle and of corneal cylinder showed lower 2000; 107:1776-1781.
Victus); Trueguide Surgical and Lensar correlation than the higher cylinder 6. Uozato H, Guyton DL. Centering corneal
FLACS (Cassini Corneal Topographer, between different devices. Hence, it surgical procedures. Am J Ophthalmol 1987;
OPE-III, Pentacam HR and AXL, Lensar). should be interpreted with caution 103:264-275.
(Sabong Srivannaboon et al JCRS 7. Camellin M, Gambino F, Casaro S.
Sensomotoric Instruments (SMI), the 2015). If different devices do not show Measurement of the spatial shift of the pupil
Image Guiding System has a Reference agreement with the astigmatic values, center. J Cataract Refract Surg 2005;31:1719-
Unit and a Surgical Pilot. In the then it should be verified using rotating 1721.
Reference Unit, a Diagnostic Image Scheimpflug devices taking posterior 8. Nienke Visser, Tos T.J.M.Berendschot et al .
which is a detailed image of Eye of astigmatism into consideration. Accuracy of toric intraocular lens implantation
blood vessels and Iris characteristics is Bibligraphy in cataract and refractive surgery. J Cataract
captured. Simultaneously , Keratometry Refract Surg 2011;37:1394 1402.
is performed at 1.9 mm ring diameter 1. Hoffman PC, Jutz WW. Analysisi of biometry 9. Michael G. Woodcock, Robert Hehmann,
using µ = 1.3320, with location of the Robert J. Cionni et al. Intraoperative
steep and flat corneal meridians shown aberrometrt versus standard preoperative
in the image. biometry and a toric IOL calculator for bilateral
toric IOL implantation with femtosecond
The Diagnostic Reference Image of laser: One – month results. J Cataract Refract
Reference Unit is matched with the Surg 2016;42:817-825.
surgical microscope image in the 10. Joshua C. Teichman, Kashif Baig, Iqbal Ike K.
Surgical Pilot Unit. The target axis, and Ahmed. Simple technique to measure toric
incision is defined and the rotational intraocular lens alignment and stability
angle translation is guided. using a smartphone. J Cataract Refract Surg
2014;40:1949-1952.
Post - Operative Assessment of Toric 11. Valentijn S.C. Webers, Noel J.C. Bauer et al.
Iol Axis: The cl assic technique for Image guided system versus manual marking
measuring the IOL axis using the for toric intraocular lens alignment in cataract
slitlamp (Figure 18) is to dilate the surgery. J Cataract Refract Surg; 2017:43:781-
pupil and rotate the slit beanm until it 788.
coincides with the IOL markings. This
technique may be complicated by not Corresponding Author:
being able to properly align the beam
with both sets fo markings cuasing an Dr. N. Z. Farooqui MS
inaccurate reading. Methods to use a D.D.U. Hospital New Delhi, India

32 DOS Times - Volume 25, Number 3, November-December 2019 www.dosonline.org/dos-times

Subspeciality-Cornea

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www.dosonline.org/dos-times DOS Times - Volume 25, Number 3, November-December 2019 33

Subspeciality-Glaucoma

Plateau Iris: Diagnosis and
Management

Shweta Tripathi MBBS, DNB, MNAMS, FMRF
Senior Consultant, Glaucoma Services Indira Gandhi Eye Hospital and Research Centre, Lucknow, India.

Glaucoma is one of the important Clinical evaluation from plateau iris.
causes of preventable blindness and the History: Hyperopic, Plateau iris was defined by the presence
number of primary Glaucoma patients of an anteriorly directed ciliary body,
is likely to increase to 60.5 million yy Younger than those with primary an absent ciliary sulcus, a steep iris root
by this year1. Primary angle closure angle closure glaucoma. from its point of insertion followed
glaucoma (PACG) may account for half by a downward angulation from the
of the subjects with primary glaucoma yy more commonly female. corneoscleral wall, presence of a central
worldwide2, the prevalence being more yy The diagnosis may be done on routine flat iris plane, and irido-angle contact12.
common in Asians. Also, it is more Plateau Iris Configuration (PIC) refers to
likely to cause visual impairment than examination or they may present a preoperative condition in which angle-
primary open-angle glaucoma3. with angle closure, spontaneously or closure glaucoma is gonioscopically
In India, the prevalence of PACG is after pupillary dilation. confirmed, but the iris is flat and the
4.32% in the Vellore Eye Study4-5. Slit lamp examination: Normal anterior anterior chamber is not axially shallow.
Non-pupil block mechanisms may be chamber depth and flat iris surface. Plateau iris syndrome refers to the
responsible for a significant proportion condition in which angle closure is
of angle closure in Asians,6 plateau iris Gonioscopy: is the gold standard for the still present confirmed by gonioscopy,
being one of them. assessment of the angle. despite a patent peripheral iridotomy
It is caused by anteriorly positioned that has removed a degree of pupillary
ciliary processes that push the yy It must be done in a darkroom block and without a shallow anterior
peripheral iris forward. The mechanical and with less bright slit beam. On chamber.
position of the ciliary processes against gonioscopic examination, the angle Complete and incomplete plateau
the trabecular meshwork crowds the is narrowed or closed. iris are defined by the level of the iris
angle and obstructs aqueous outflow relative to Schwalbe’s line and the
through trabecular meshwork7-8. A yy On indentation gonioscopy the structures of the angle wall (Figure 1),
component of pupillary block is often Double hump sign (also known as (Figure 2).
present. sine wave) is seen. Ultrasound biomicroscopy (UBM).
Plateau iris is one of the most frequent Can be utilized for explaining the
causes of primary angle-closure yy Peripheral “hump” (Of the double mechanism of plateau iris syndrome,
glaucoma in young patients, the mean hump) is created by the iris draping for diagnosing and detecting the
age at the first presentation for plateau over the ciliary body and the more anatomical changes
iris syndrome is 40 years9. central hump by the iris curving over ASOCT: is not a dynamic examination
It is seen most commonly in women. the anterior lens surface11. and does not provide as much
The prevalence is increased in patients information as gonioscopy.
with a family history of plateau iris yy These changes found in gonioscopic
syndrome and the predisposition may indentation cannot be observed in Differential diagnosis
be of autosomal dominant inheritance eyes with primary angle closure yy Pseudo plateau iris” caused by iris
pattern10. due to pupillary block More force
is needed to open the angle on cysts13. or ciliary body cysts
indentation in plateau iris than
in pupillary block angle closure
because the ciliary processes must be
displaced.

yy Closed angle after patent iridotomy,
can indicate residual angle closure

34 DOS Times - Volume 25, Number 3, November-December 2019 www.dosonline.org/dos-times

Subspeciality-Glaucoma

C: cornea; SL: Schwalbe’s line; NTM: Nonpigmented irabecular meshwork; PTM: pigmented ache, and retinal detachment.
trabecular meshwork; SS: scleral spur.
Figure 1: Position and types of plateau iris in relation to the IOP rising possibility. Modified Compliance by the patient plays a
from: Ritch R, Lowe RF. Angle-closure glaucoma clinical types. In: Ritch R, Shields MB, pivotal role in the success of the medical
Krupin T, edtors. The glaucomas. Saint Louis: Mosby; 1996, p.831-40. treatment.

Figure 2: Schematic UBM picture showing the structures which can be assessed in plateau Laser Iridotomy
iris. Should always be the choice of
treatment. It excludes any associated
yy Primary angle closure trabecular meshwork and opening the pupillary block and helps to confirm
Medical treatment anterior chamber angle and lowers the plateau iris syndrome diagnosis. A
Miotic agents are an option for patients IOP by stimulating contraction of the patent iridotomy is a prevention
who do not consent to laser treatment. ciliary muscle, thereby increasing the procedure that reduces the risk of angle
trabecular outflow of aqueous humor. closure. Even after iridotomy has opened
These drugs cause the pupillary The adverse effects could be Induced the angle in a satisfactorily manner,
sphincter to contract, mechanically myopia, pupillary constriction, brow periodic gonioscopy is still essential
pulling the iris away from the because the angle may narrow with
age or patients may have incomplete
plateau iris syndrome. Patients with
plateau iris configuration must not be
assumed to be cured and plateau iris
syndrome may develop years later14.

Argon Laser Peripheral Iridoplasty
It is the definitive treatment and the
procedure of choice that opens the
angle in case of plateau iris syndrome.
It is indicated when laser iridotomy is
not efficient. ALPI is highly useful in
the reduction of appositional closure
of the iris periphery to the trabecular
meshwork and in opening the angle.
This procedure reduces the risk of later
synechial formation15.

The burns should be made in the
peripheral iris, causing the iris to shrink
and pull away from the angle. A spot
size of 200 to 500 µm, a duration of 0.2
to 0.6 seconds, and a power of 150 to
300 mW can be used to perform this
procedure.

Surgical Intervention
Indication

Patients who present with advanced
plateau iris, compromised trabecular
meshwork function, and severe
synechial angle closure involving more
than 180º of the trabecular meshwork.

Pupillary dilation should be avoided
or performed minimally with a short-
acting compound such as tropicamide
(that can be readily reversed.

www.dosonline.org/dos-times DOS Times - Volume 25, Number 3, November-December 2019 35

Dr. Shweta Tripathi
Senior Consultant Glaucoma Services Indira

Subspeciality-Glaucoma

24 Hour Intraocular Pressure
Monitoring: The Future is Here

Shibal Bhartiya MS
Senior Consultant, Dept of Ophthalmology, Fortis Memorial Research Institute, (FMRI), Gurugram, Haryana, India

Intraocular pressure (IOP) has been is essential for picking up episodic entoptic phenomenon of pressure
known to be the single most important arrhythmias, 24 hour IOP recording can phosphenes to evaluate IOP.
risk factor, and the only modifiable one, provide a wealth of clinically relevant
when it comes to glaucoma progression. information. The iCare home tonometer is a
In addition, fluctuation in circadian IOP hand-held unit which measures the
has been reported to be one the major This article aims to highlight the deceleration of a magnetized probe in
risk factors for visual field progression currently available modalities for an electromagnetic field on the rebound
in both primary open closure glaucoma continuous IOP monitoring. from the cornea.
(PACG) and primary open angle
glaucoma (POAG) patients. Both, short Current methods for 24 hour IOP While both of these tonometers are well
term variation in IOP represent the recording accepted by patients, there are certain
nyctohemeral pattern, as well as IOP As on date, there are three modalities drawbacks to their use. Once again,
spikes, have been related to glaucoma which can provide information about the patient has disturbed sleep, and the
progression. While there is no denying IOP behaviour over 24 hours. These measurements cannot be performed
the clinical utility of recording diurnal include: in the supine position, patients
variation of IOP using the Goldmann often forget to take readings, and can
Appalanation tonometer (GAT), these yy Self tonometry. undergo considerable stress during the
recordings have several flaws. yy Temporary continuous monitoring IOP recordings. Despite this, they are
relatively cheaper to use, measure the
The problems with measuring diurnal device. IOP at home for patients and obviate the
variation of IOP (DV) with GAT include: yy Permanent continuous monitoring need for hospitalisation.

yy Logistics and cost of hospitalisation device. Temporary Continuous Monitoring
of patient for DV. Patient Self Tonometry Devices
While the concept of home tonometry The contact lens sensor (CLS,
yy Inter-observer variability of IOP measurements is not new, the Triggerfish, Sensimed, Switzerland)
recording unless the same person methodology is. There are several hand consists of a disposable silicon contact
uses the same device round the clock. held, portable IOP monitoring devices; lens with an embedded micro electrical
these include the Perkins, TonoPen system, which measures changes in
yy No supine measurements possible, (Mentor, Norwell, Mass), Zeimer and corneal curvature induced by variation
so the physiological body position coworkers’ selftonometer, Ocuton-S in IOP. Embedded within the CLS are
is not maintained during night time (EPSa Elektronik and Praezisionsbau, two strain gauges, a microprocessor and
recordings. Saalfeld, Germany), iCare Pro, iCare an antenna. The strain gauges detect
ic100, 200 and ProTon (Tomey, changes in corneal shape, and transmits
yy Sleep wake cycle, which is one of Erlangen, Germany). However, they are the information to an adhesive antenna
the most important determinants not self tonometers. The self tonometers that is attached to the orbit of a patient.
of IOP fluctuation is disturbed, as are easy to learn, and do not require The adhesive antenna sends information
the patient has to be woken up, and anesthetic eye drops or any specialized to the portable recorder worn by the
needs to sit up for each IOP recording. skills for use. patients. This Triggerfish takes 300 ‘IOP’
readings over 30 second period every
Twenty four hour IOP monitoring, The Proview eye pressure monitor 5 minutes, for a total of 86,400 data
therefore, is a significant advancement (Bausch & Lomb, Rochester, NY) uses points over a 24 hour period. The data
in combating glaucoma. Analogous a psychophysical test based on the
to a continuous ECG record, which

www.dosonline.org/dos-times DOS Times - Volume 25, Number 3, November-December 2019 37

Subspeciality-Glaucoma

are sent by blue tooth connection to a Figure 1: Continuous 24 hour IOP monitoring in a patient of glaucoma, showing the classic
computer for analysis. The data points nocturnal rise in eye pressure.
are measured in millivolts or millivolt
equivalent, and provide an index of IOP Figure 2: Triggerfish Contact Lens Sensor
fluctuation, but no absolute IOP values.
In the ARGOS study protocol, 6 patients tolerated and effective in measuring
The device has been for approved with well controlled POAG/NTG with IOP over time.
for clinical use by the USFDA, and visually significant cataract who were
there is sufficient data to suggest scheduled for cataract surgery, were Conclusion
that it provides an accurate and recruited for implantation of the device. Smart contact lens sensors, intraocular
clinically useful measure of diurnal This device was implanted in the sulcus, implants and home monitoring devices
IOP fluctuation. The device is well during uneventful cataract surgery, and are leading the advances in innovation,
tolerated, and ’IOP’ recordings continue monitored for position and placement and 24 hour IOP monitoring has
uninterrupted during sleep and waking using UBM. It was found to be well caught the imagination of glaucoma
hours, and actually provide an accurate
representation of IOP fluctuations over
the 24 hour period. In fact, the IOP
fluctuations during exercise, sleep and
and day to day activities can be very
well documented by the CLS (Figure
1,2).

Currently, limitations to its widespread
use include high cost of the device,
absence of measurement of absolute
IOP, and issues pertaining to patient
acceptance of this device.

Permanent Continuous
Monitoring Device
Implandata Ophthalmic Products,
GmbH Germany, has introduced an
implantable intraocular device called
the Implandata Eyemate which is
currently undergoing human clinical
trials. It consists of a wireless intraocular
transducer (WIT) that has 8 pressure and
temperature sensors, an identification
and analog to digital encoder as well as
telemetry unit. It is a pressure-sensing
eye implant containing a microchip
together with an external hand held
device which transfers energy wirelessly
to the implant and receives readings
from it. This device can generate range
of settings that allow for monitoring
at variable intervals, ranging from
one to two intraocular pressure
measurements per day to continuous
24 hour monitoring. The system is
designed to enable home monitoring
of intraocular pressure and remote
patient management. It is presumed
that the device will be durable enough
to accurately sense intraocular pressure
for 10-15 years.

38 DOS Times - Volume 25, Number 3, November-December 2019 www.dosonline.org/dos-times

Subspeciality-Glaucoma

practitioners and researchers 5. Hughes E, Spry P, Diamond J. 24-hour patients with glaucoma (ARGOS study):
worldwide. In the future, these may monitoring of intraocular pressure in 1-year results. Invest Ophthalmol Vis
enable patients to take daily or hourly glaucoma management: a retrospective Sci.2015;56:1063–9.
measurements of their eye pressure, review. J Glaucoma. 2003;12:232–6. 12. Lorenz K, Korb C, Herzog N, et al.
which may be remotely communicated Tolerability of 24-hour intraocular
to their glaucomatologist, and which 6. Barkana Y, Anis S, Liebmann J, Tello C, pressure monitoring of a pressure-
would help their doctors to tailor more RitchR. Clinical utility of intraocular sensitive contact lens. J Glaucoma
effective and individualised treatment pressure monitoring outside of normal 2013;22:311–16.
plans. office hours in patients with glaucoma. 13. Mansouri K, Medeiros FA, Tafreshi
Arch Ophthalmol. 2006;124:793–7. A, Weinreb RN. Continuous 24-hour
Suggested Reading monitoring of intraocular pressure
7. Liu JHK, Weinreb RN. Monitoring patterns with a contact lens sensor:
1. Bhartiya S, Gangwani M, Kalra RB, intraocular pressure for 24 h. Br J safety, tolerability, and reproducibility
Aggarwal A, Gagrani M, Sirish KN. 24- Ophthalmol. 2011;95:599–600. in patients with glaucoma. Arch
hour Intraocular pressure monitoring: Ophthalmol. 2012;130:1534–39.
the way ahead. Rom J Ophthalmol. 8. De Smedt S. Noninvasive intraocular
2019;63:315-320. pressure monitoring: current insights. Corresponding Author:
Clin Ophthalmol.2015;9:1385–92.
2. Bhartiya S, Wadhwani M, Rai O, Patuel Dr. Shibal Bhartiya
M, Dorairaj S, Sirish KN. Diurnal 9. Moreno-Montane˜ s´ J, Martın´ ez-de- Senior Consultant, Dept of Ophthalmology,
Variation of IOP in Angle Closure la-Casa JM,Sabater AL, Morales- Fortis Memorial Research Institute, (FMRI),
Disease: Are We Doing Enough? Rom J Fernandez L, Sae´ nzC, Garcia-Feijoo J. Gurugram, Haryana, India
Ophthalmol.2019;63:208-216. Clinical evaluation of the new rebound
tonometers iCarePRO and iCare
3. Clement CI, Bhartiya S, Shaarawy T. ONE compared with the Goldmann
New perspectives on target intraocular tonometer.J Glaucoma. 2015;24:527–32.
pressure. Surv Ophthalmol. 2014;59:615-
26. 10. Dabasia PL, Lawrenson JG, Murdoch IE.
Evaluation of a new rebound tonometer
4. Asrani S, Zeimer R, Wilensky J, Gieser D, for self-measurement of intraocular
Vitale S, Lindenmuth K. Large diurnal pressure. Br J Ophthalmol. 2016
fluctuations in intraocular pressure are 100:1139-43.
an independent risk factor in patients
with glaucoma. J Glaucoma 2000;9:134– 11. Koutsonas A, Walter P, Roessler G,
42. PlangeN. Implantation of a novel
telemetric intraocular pressure sensor in

www.dosonline.org/dos-times DOS Times - Volume 25, Number 3, November-December 2019 39

Subspeciality-Glaucoma

A Neglected Case of Phacolytic
Glaucoma

Barkha Gupta1 MD, Neha Midha2 MD, Dewang Angmo1 MD, DNB, FRCS, FICO, MNAMS
1. Dr. R.P.Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
2. Advanced Eye Care and Glaucoma Services, New Delhi, India.

Purpose: To report a case of neglected phacolytic glaucoma.
Case description: Elderly female presented with complaints of recent onset pain and redness in left eye. On examination, right eye had
early cataract with visual acuity of 20/70. Left eye had no perception of light with hypermature sclerotic nucleus displaced into the anterior
chamber, intraocular pressure of 44 mmHg and total glaucomatous cupping. Patient was diagnosed to have left eye phacolytic glaucoma
and underwent lens extraction with anterior vitrectomy.
Conclusion: Delay in diagnosis and treatment of mature senile cataract can lead to lens induced glaucoma and compromise the final visual
outcomes.
Keywords: Phacolytic glaucoma, lens induced glaucoma, hypermature cataract.

The crystalline lens has been implicated diminution of vision in both eyes homatropine 2%, prednisolone acetate
to cause glaucoma by numerous (left more than right) since 2 years. 1%, brinzolamide 1% and, timolol 0.5%
mechanisms, more often in elderly On examination, the visual acuity and brimonidine 0.2% combination.
population1. While an intumescent was limited to 20/70 in right eye (RE) Oral acetazolamide was given in
cataractous lens can cause pupillary and perception of light in left eye preoperative period. Lens extraction
block and lead to phacomorphic (LE). RE had immature senile cataract with anterior vitrectomy was done on
glaucoma, a hypermature senile (IMSC) with nuclear sclerosis grade day 3 after control of IOP on maximal
cataract can lead to phacolytic 2. LE had circumcorneal congestion, tolerable medication. Post operatively,
glaucoma by leakage of soluble lens corneal edema, pigment deposits on topical moxifloxacin 0.5% was added
proteins into the anterior chamber; lens endothelium and hypermature sclerotic to the on going treatment. At day 7,
particle glaucoma after disruption of nucleus displaced into the anterior her pain and redness were relieved and
anterior lens capsule; or phacoantigenic chamber alongwith vitreous (Figure 1). she maintained IOP of 16 -18 mmHg
glaucoma due to granulomatous No cortical matter was visible. There on 3 anti-glaucoma medications at 3
inflammatory reaction directed were cells++ and flare+ in anterior and 6mths follow up. The patient and
against own lens antigens. Incidence chamber. There were no keratitic relative were counselled regarding the
of lens induced glaucoma is higher precipitates on corneal endothelium, importance of follow up of the fellow
in developing countries and lower hypopyon, signs of pseudoexfoliation, eye and timely management to prevent
socioeconomic strata of the society due history of trauma/surgery or systemic blindness in fellow eye as well.
to lack of awareness and poor access illness. On gonioscopy angles were
to health facilities2. In this article, we open in both eyes and intraocular Discussion
report a case of neglected and untreated pressure was 18 and 44 mmHg in RE Phacolytic glaucoma is an inflammatory
phacolytic glaucoma in an elderly and LE respectively. Optic nerve head condition caused by the leakage of
female from a rural part of northern examination revealed cup to disc ratio proteins through the capsule of a mature
India. of 0.3:1 in RE and total glaucomatous or hypermature cataractous lens3. With
cupping in LE (hazily seen). Patient advancing age, the protein composition
Case was diagnosed to have RE IMSC and LE of crystalline lens becomes altered,
A 64 years old female, resident of a phacolytic glaucoma with hypermature with an increased percentage of high-
village in Haryana, presented with senile cataract. Patient was medically molecular-weight protein. In a mature
severe pain, and redness in left eye since managed to control the inflammation or hypermature cataract, these proteins
twenty days and gradual progressive and IOP. Patient was started on topical are released through microscopic

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Subspeciality-Glaucoma

Figure 1: Anteriorly Displaced hypermature sclerotic nucleus with vitreous in anterior the optic nerve head and complete
chamber. No cortical matter is visible. resorption of cortical matter.
Another important cause of phacolytic
openings in the lens capsule, which anterior chamber excludes the diagnosis glaucoma is relatively good vision
are engulfed by the macrophages. of phacoantigenic and phacomorphic in fellow eye either due to minimal
These areas of leakage are visible as glaucoma respectively. Lens particle cataract as in our case or due to
white soft patches on the anterior glaucoma was ruled out, as there was no contralateral pseudophakia6.
capsule. These macrophages along with history of trauma or cataract surgery in Spreading awareness among patients
the other inflammatory cells lead to left eye. for regular health/eye check up after
trabecular meshwork obstruction and In the studies published by Prajna et 40yrs. Also, explaining them the
rise in intraocular pressure. The typical al4 and Pradhan et al5 on lens induced importance of timely cataract surgery
presentation of phacolytic glaucoma glaucoma, both phacomorphic and and not waiting until the white reflex is
is a red and painful eye with gradual phacolytic glaucoma were more visible is vital in reducing the incidence
decrease in vision due to maturation common in elderly females and visual of lens induced glaucoma. Proper
of cataract. Diagnosis is usually made outcomes were poor in cases where a counselling for fellow eye surgery in
by the presence of corneal edema, delay of more than 5-10 days was noted unilateral pseudophakes is necessary. In
raised IOP, prominent cells and dense between onset of pain and surgery. the event of phacolytic glaucoma early
flare in anterior chamber, open angles Distance from the hospital was also presentation and prompt management
on gonioscopy, mature cataract and inversely related to visual outcomes. may improve visual outcomes.
white material/particles in the anterior In our case also, patient was an elderly
chamber. Pseudohypopyon may also be female from a rural area with poor References
present (lens protein deposits layering access to health facility. It was a long
in the inferior angle). Flare response in standing, neglected case as was evident 1. Papaconstantinou D, Georgalas I, Kourtis N, et
absence of keratic precipitates and deep from total glaucomatous cupping of al. Lens-induced glaucoma in the elderly. Clin
Interv Aging. 2009;4:331–336. doi:10.2147/
cia.s6485

2. Dhar GL, Bagotra S, Bhalla A. Lens induces
glaucoma – A clinical study. Indian J
Ophthalmol 1984;32:456-9.

3. Ellant JP, Obstbaum SA. Lens-induced
glaucoma. Doc Ophthalmol. 1992;81:317–
338.

4. Prajna RV, Ramakrishnan R, Krishnadas R,
Manoharan N. Lens-induced glaucomas-
visual results and risk factors for final visual
acuity. Indian J Ophthalmol. 1996;44:149–
155. [PubMed] [Google Scholar]

5. 48. Pradhan D, Hennig A, Kumar J, Foster A. A
prospective study of 413 cases of lens-induced
glaucoma in Nepal. Indian J Ophthalmol.
2001;49:103–107.

6. Agarwal, R., Bhardwaj, M., Patil, A., &
Sharma, N. (2019). Phacolytic glaucoma
in contralateral pseudophakes. Clinical
and Experimental Optometry. doi:10.1111/
cxo.12986.

Corresponding Author:

Dr. Dewang Angmo MD, DNB, FRCS,
FICO, MNAMS
Dr. R.P.Centre for Ophthalmic Sciences,
All India Institute of Medical Sciences,
New Delhi, India

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Subspeciality-Glaucoma

Rebound Tonometers-A General
Review

Prerna Garg, Suneeta Dubey
Dr. Shroff Charity Hospital, Darya Ganj, New Delhi, India.

Abstract: Rebound tonometer is commercially available as Icare (Tiolat Oy, Helsinki, Finland) devised by Kontiola in 1997 and introduced
in the market in 2003. This tonometer is based on the rebound measuring principle, in which a very light-weight probe (26.5 mg) makes a
momentary contact with the cornea. Deceleration and the contact time of the probe depend on the IOP of the eye. Hence, higher the IOP, the
faster the probe decelerates and the shorter the contact time. There are different Icare devices available, TA01i being the oldest and ic200
being the newest model.

The concept of rebound tonometer Figure 1. Parts of Rebound Tonometer to travel towards the cornea at a velocity
(RBT) aka induction/impact tonometer processing electronics. The probe is a of approximately 0.2 metres per second.
was introduced by Obbink more than gold plated stainless steel wire (which The probe impacts, decelerates and
60 years ago. According to him, when enables probe’s accurate movement in rebounds from the anterior corneal
a small probe is fired at the corneal the magnetic field) with a small plastic surface. The voltage induced in the
surface and its rebound velocity is tip made of medical grade plastic that solenoid coil by the movement of the
measured, it will correlate with the gently touches the cornea. It is 40 mm magnetized probe is then processed
intraocular pressure (IOP) of the eye. long, 0.3 mm in diameter with a 1.7 by signal processing electronics and
Dekking improved the technique mm diameter plastic end tip, and has microcontrollers which derive the IOP
thirty years later but it was not brought a mass of 26.5 mg. It moves within on the basis of the deceleration speed
into widespread use until 1997 when the solenoid housing on Teflon™ and time of the probe on contact with
Kontiola et al1 devised an improved and bearings. The application of a transient the cornea2.
simpler version which commercially (approximately 30 ms) electrical Validation of this measurement
became available as Icare tonometer current to the solenoid causes the probe
(Tiolat Oy, Helsinki, Finland) in 2003.

Principle- This tonometer is based on
the rebound measuring principle, in
which a very light-weight probe (26.5
mg) makes a momentary contact with
the cornea. In this rebound technology,
motion parameters of the probe are
recorded during the measurement.
These motion parameters are measured
using an induction based coil system.
An advanced algorithm analyses the
deceleration and the contact time of
the probe while it touches the cornea.
Deceleration and the contact time of
the probe depend on the IOP of the eye.
Hence, higher the IOP, the faster the
probe decelerates and the shorter the
contact time.

The measurement system comprises
of a solenoid, magnetized probe and

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Subspeciality-Glaucoma

Figure 5. Icare Home

Figure 2. Tip of the probe is kept perpendicular and at a distance of 4-8 cm from cornea. perpendicular to the cornea and at
a distance of 4-8 mm from it (Figure
Figure 3. Intraocular pressure measurements 2).
system on enucleated rodent eyes has obtained with the system also appear
shown that the inverse of the probe’s to be tolerant to variations in the initial 4. The measuring button is pressed
deceleration time correlates well with cornea-probe distance and angle of lightly. The tip of the probe should
manometric determination of IOP probe impact2,4. touch the central cornea.
between 5mmHg and 60 mmHg)3.
Measurement 5. Six measurements are made. After
1. The patient is asked to relax and every measurement the instrument
gives a short beep. Once all the six
look straight ahead at a specific readings are taken, it gives a long
point. beep. Double beep indicates an
2. The forehead support is adjusted on error. Then the highest and lowest
the forehead and the tonometer is values are discarded and the average
brought near the patient’s eye. of the remaining four readings is
3. The tip of the probe is kept displayed (Figure 3).

6. The letter P (Figure 4) appears on
the display, followed by the IOP
reading.

Figure 4. Figure 6. Indicators in Icare home.

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Subspeciality-Glaucoma

Figure 7.

If the P is blinking, it means that can occur during the measurements in Figure 8. Icare ic200.
the standard deviation (SD) of the general ophthalmic practice. Takenaka
measurements is greater than normal. et al reported that IOP measurements reading clear and easy to perceive.
P_ (line down): SD is only slightly greater, in the peripheral cornea 2 mm from Yellow or red display indicates than
reading is reliable the limbus in the nasal and temporal the procedure needs to be repeated,
P-- (line in the middle): SD is clearly regions were approximately equal to whereas a green display indicates that
greater than normal, new reading if IOP the IOP measured with the GAT5. The the IOP measured is accurate.
is >19 mm Hg. disadvantage of this model is that the Icare ONE/ HOME
P-- (line up): SD is much greater than probe can fall out if the tonometer is Icare HOME is a self-monitoring
normal, new reading has to be taken. facing downward. Hence measuring tonometer designed for home use
If there is an inaccurate measurement, IOP in supine position is difficult with by patients who require regular IOP
the tonometer will beep twice and this. To solve this problem, patients monitoring. It is an updated version of
display an error message. should lie on their left side (i.e. left Icare ONE (no longer available for sale).
Maintenance- lateral position) when the right eye It is equipped with eye recognition
The Icare® rebound tonometer does not is measured (and vice versa). The sensors (that detect which eye is being
require any maintenance calibration measurement values for the lower eye observed) and positioning sensors (to
or regular service. The probe base has will be artificially yet significantly ascertain whether it is held upright).
to be cleaned once every 6 months or higher than those for the upper eye The instrument is 11-8-3 cm in size,
if the error messages E01 or E03 are because of the postural change required and 150 gms in weight. The patient has
displayed. It can be cleaned by soaking for the supine position6. to hold the tonometer in front of their
in a container filled with 70-100 % face without any vertical or horizontal
isopropyl alcohol for 15-30 minutes. Icare PRO tilt and press the measurement button.
The probe is disposable and needs to be In 2011 iCare released this updated The device is in the correct position
changed after every patient. model with features including a built- when the patient can see a “green” ring
Different Icare devices- in inclination sensor that enables IOP
measurement in the supine position.
Icare TA01i It has a shorter probe around 14 mm
It is the original model of Icare released in length which does not fall out when
in 2003 based on the description by the tonometer is not upright. Also it has
Kontiola. It weighs around 250 gms and improved accuracy and displays the IOP
does not have a position sensor. Hence it data to the first decimal place. It is easy
is more flexible than the revised newer to use, especially for measuring IOP
models, particularly in children who are when children are sleeping in a supine
non-compliant. Beasley et al reported position in the clinic. The position
that Icare TA01i is not affected by small sensor allows IOP to be measured in
deviations of the probe (within 10°) that both horizontal and vertical positions.
A slight tilt of the instrument from
either of the positions prevents the
probe from being launched.

It has a colour display to make each

44 DOS Times - Volume 25, Number 3, November-December 2019 www.dosonline.org/dos-times

Subspeciality-Glaucoma

around the probe. When the instrument of the instrument. method for measuring intraocular
is not held correctly, the ring signal pressure. Doc Ophthalmol. 1997;93:265–
shows up in “red.” Also, if the probe is It has a Bluetooth functionality for 276.
too close or far from the eye, or if the wireless printing and data transfer. It 2. Kontiola AI. A new induction-
patient’s hair or hands are in the way, also has options of adjusting the beep based impact method for measuring
the ring signal will flash red with an sound, probe base light brightness and intraocular pressure. Acta Ophthalmol
error beep. Even slight malposition of brightness of the display screen. Scand. 2000;78:142–145.
the instrument prevents the probe from 3. Danias J, Kontiola AI, Filippopoulos T,
being launched. The measurement data Advantages of Icare rebound tonometer Mittag T. Method for the noninvasive
is not displayed on the panel, instead over other tonometers measurement of intraocular pressure
the device has to be connected to a PC in mice. Invest Ophthalmol Vis Sci.
installed with the Icare LINK software 1. When compared with Goldmann 2003;44:1138–1141
program. The information stored in the applanation tonometer (GAT- Gold 4. Beasley IG, Laughton DS, Coldrick
program includes the IOP in mmHg, standard) - BJ, Drew TE, Sallah M, Davies LN.
time and date of the measurements, Does rebound tonometry probe
identification of the eye (right or left), yy No topical anaesthesia and misalignment modify intraocular
and quality level of each measurement. fluorescein staining pressure measurements in human eyes?
J Ophthalmol. 2013;2013:791084.
Icare ic100 yy No slit lamp mounting, 5. Takenaka J, Mochizuki H, Kunihara
Icare ic100 is an updated version of yy No unnecessary infection care due to E, Tanaka J, Kiuchi Y. Intraocular
Icare TA01i, released in 2016. It has a pressure measurement using rebound
positioning sensor unlike Icare TA01i. the use of a disposable probe. tonometer for deviated angles and
Therefore, the probe has to be kept yy It is light weight and portable. positions in human eyes. Curr Eye Res.
in a horizontal position closer to the yy Can measure IOP with patient in any 2012;37(2):109–114.
corneal center. If malpositioned, the 6. Lee JY, Yoo C, Jung JH, Hwang YH,
probe will not be launched. The result position- standing, sitting, reclining, Kim YY. The effect of lateral decubitus
appears on the display screen with supine, lateral. position on intraocular pressure
a green circle (OK), a yellow circle yy Can measure IOP over soft contact in healthy young subjects. Acta
(acceptable variation) or “repeat” (too lenses. Ophthalmol. 2012;90(1):e68–e72.
much variation). It is difficult to use yy Can measure IOP in patients with 7. Baudouin C, Gastaud P. Influence
in children, patients in wheelchairs, central corneal abnormalities. of topical anesthesia on tonometric
and handicapped persons, compared to 2. It does not require an air puff values of intraocular pressure.
Icare TA01i because of its strict position compared to the conventional non Ophthalmologica. 1994;208:309–13.
sensor. contact tonometers, hence easier to
measure IOP in children. Corresponding Author:
Icare ic200 3. It can measure IOP in children
This is the newest model launched in without the need for general Dr. Prerna Garg
2019, and received FDA clearance this anaesthesia or sedation. Dr. Shroff Charity Hospital, Darya Ganj,
year. It is designed for professional use 4. The IOP measured by this is not New Delhi, India.
in the surgical operation room and affected by local anaesthesia. It
emergency room as well as the clinic. has long been shown that local
It allows measurement whether the anaesthetic drops can alter the IOP7.
patient is sitting, standing, half-sitting However, it cannot replace GAT as the
or in the supine or lateral recumbent gold standard, since it has been found
position. to overestimate the IOP more so when
the IOP is greater than 22 mmHg. Also,
An indicator at the probe base confirms similar to GAT, the IOP readings by
the position of the tonometer prior to Icare are also affected by biomechanical
measurement. Green light indicates properties of cornea.
that the measurement is reliable and
red light indicates incorrect positioning References
1. Kontiola AI. A new electromechanical

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Subspeciality-Glaucoma

Monitoring Glaucoma Progression
with Visual Fields

Dewang Angmo1 MD, DNB, FRCS, FICO, MNAMS Talvir Sidhu2 MD, Neha Midha3 MD
1. Dr. R.P.Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
2. Government Medical College Patiala, Punjab.
3. Advanced Eye Care and Glaucoma Services, New Delhi, India.

Abstract: Visual field examination is an integral part of glaucoma diagnosis and management. Glaucoma progression may be noted even
if target IOP is maintained at all visits to the clinic. In this setting, it is important to be well-versed in evaluating progression using visual
field examination. Clinician should be capable of differentiating short term and long term fluctuations from true progression. Six visual field
examinations in first two years of diagnosis are recommended to get a definite baseline and to identify fast progressors. Progression is often
seen as deepening or enlargement of pre-existing scotoma. Both event and trend based analysis give a useful insight in analyzing progression
of the disease.
Keywords: Glaucoma, Progression, Visual Field.

Glaucoma is a progressive disease and true progression, one has to evaluate field, one should not wait another year
therefore periodic optic disc evaluation whether the observed change exceeds to proceed with a confirmatory test, but
and visual field examination are the expected fluctuation in the tested instead the frequency of examinations
pertinent for its management. Detecting area. should again be increased in order to
progression in a chronic and slowly confirm or exclude progression.
progressive disease like glaucoma Frequency of visual field Visual field progression in glaucoma
is difficult. This article highlights examination to assess glaucoma may be seen as:
the important aspects of detecting progression Most often progression is identified
progression on visual fields. On serial Most glaucoma patients under as a deepening of a preexisting
visual field examinations, it is often treatment will have slow rate of scotoma (as shown by various research
difficult to differentiate between normal progression over the years, but there studies), along with enlargement of
short and long-term fluctuations and are those few who will have rapid the scotoma. In a study evaluating
true disease progression. Due to these progression rates. Published rates for visual field progression in glaucoma,
fluctuations, a new change on a visual mean deviation (MD) deterioration most cases showed deepening (86%)
field needs to be confirmed on repeat in glaucoma patients are variable and or enlargement (23%) of a previous
testing. depend on individual susceptibility, scotoma, while none of the eyes
severity of disease, and treatment developed new visual field defects
Fluctuation versus Progression strategies. One should perform enough in previously normal areas2. This
.Fluctuation is defined as the variability visual fields at the beginning of follow- highlights the importance of evaluating
in the response to the same stimulus that up in order to detect cases that present areas adjacent to existing scotomas
is not due to true disease progression. with fast progression rates. It has when searching for visual field
As visual fields testing is a subjective been suggested that six visual field progression. However, these adjacent
examination, variable responses may be examinations be done in the first 2 areas are also known to exhibit larger
obtained each time the test is performed years, in order to rule out aggressive degrees of fluctuation, which makes
(inter-test or long-term fluctuations) or disease and to establish a consistent identification of true progression more
during the same test (intra-test or short- baseline. Subsequently, the frequency difficult. Diffuse sensitivity loss may
term fluctuations). Fluctuation varies of testing may be reduced to once or also represent glaucoma progression,
among patients and among sectors in twice yearly as long as no change is although it is usually accompanied by
the same visual field, and increases detected. At any time during follow-up new defects or worsening of previous
with severity of disease1. To detect that a change is identified on the visual

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Subspeciality-Glaucoma

focal defects. Progressive diffuse loss Figure 1: Overview Analysis. is based on the total deviation plot, it is
should raise the suspicion of cataract The older software version is the affected by diffuse media opacities such
progression and must be correlated Glaucoma Change Probability (GCP) as cataract.
with clinical examination3. software. The GCP performs individual The new Guided Progression Analysis
The Humphrey field analyzer (HFA) comparisons of each visual field point (GPA) software was developed to
has statistical software, STATPAC, on follow-up examinations with a set of overcome the limitations mentioned
which is capable of analyzing a single baseline fields. Progression is flagged if above. Both the GCP and the GPA are
visual field for abnormalities or a series two or more adjacent points within or event based analyses, but the GPA has
of fields for progression. The Single adjacent to an existing scotoma show following advantages when compared
Field Analysis provides a printout of a significant deterioration confirmed with the GCP.
single visual field with most detailed on two consecutive tests. The GCP • The GPA is based on the pattern
information about that test. In the performs individualized analysis of the
Overview printout, several visual fields sectors in the visual field; however, as it
are arranged chronologically on the
same page for the ease of comparison
(Figure 1). The Change Analysis
printout provides a chronologic box
plot analysis, the time course of the four
global indices Mean Deviation (MD),
the Pattern Standard Deviation (PSD),
the Short Term Fluctuation (SF), and the
Corrected Pattern Standard Deviation
(CPSD).
(Only MD and PSD in SITA), and the
linear regression analysis of MD.

Event and Trend based analyses
There are two main approaches to
analyze progression -- event-based and
trend-based analyses. The first approach
compares the current examination with
apreviousone(usuallythebaselinetest).
If the results are significantly worse on
the follow-up examination, progression
is indicated. This is called event-based
analysis. In the second approach, instead
of only comparing a few tests, one looks
for progressive change by analyzing all
the tests available in a specific period
of time. This is called trend-based
analysis, as the trend in the values is
plotted over time, and observing the
slope or decline of the regression line
can assess significant deterioration.
Besides evaluating whether progression
has occurred, trend-based analysis
also allows an estimation of the rate
of progression. It is well known that
some patients deteriorate faster than
others, and estimating each individual’s
rate of progression may help decide
aggressiveness of treatment and the
response to treatment.

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Subspeciality-Glaucoma

Figure 2: Likely Progression. the baseline tests. However, one can Progression. If the same three or more
override this automatic selection to a points have significant change detected
deviation plot, as opposed to the more suitable time-point (e.g., change and repeated in three consecutive
total deviation plot used by the in therapy after progression), or to reject follow-up tests, the GPA software will
GCP. Therefore, the GPA evaluates fields that are unreliable due to initial flag the last examination as Likely
progression adjusted for diffuse learning effects (which could reduce Progression (Figure 2).
effects. the sensitivity to detect progression).
• The GPA runs not only on SITA The GPA software then compares each The latest version of the Humphrey
tests, but also accepts full-threshold follow-up test to the average of the field analyzer provides the visual field
tests for the baseline pair (the GCP baseline tests. It identifies points that index (VFI) and VFI progression plot.
did not), which is convenient as show change greater than the expected The VFI is a newly developed index
some patients with long-term variability (at the 95% significance that is proposed to evaluate the rate of
follow-up have been tested with the level), as determined by previous progression4. The aim of this analysis
full-threshold strategy during early studies with stable glaucoma patient. is not to detect progression, which can
follow-ups. If significant change is detected in at be done with the GPA, but to provide
Asdetectionofneworprogressingvisual least three points, and is repeated in valuable information on the rate of
field defects is performed by comparison the same points over two consecutive deterioration. The VFI is calculated as
to the baseline, it is imperative to have follow-up tests1 then the GPA software the percentage of normal visual field,
reliable baseline examinations. The will flag the last examination as Possible after adjustment for age. Therefore, a
software automatically selects the VFI of 100% represents a completely
first two available examinations as normal visual field, while a VFI of
0% represents a perimetrically blind
visual field. The VFI is shown on the
GPA printout both as a percent value
for each individual examination and
as a trend analysis, plotted against age.
While the MD is based only on the
total deviation map, and thus is largely
affected by cataract, the VFI is based
both on the pattern deviation and the
total deviation probability maps. The
former (pattern deviation) helps in the
identification of possibly progressing
points, and the latter (total deviation) is
used for the actual calculation of change
of the total deviation value. In addition,
the VFI algorithm gives weightage for
different locations, giving more weight
to the central points. The final VFI score
is the mean of all weighted scores. For
glaucoma patients with worsening
cataract, however, the VFI showed a
slower rate of progression than the
MD, which would be a more accurate
representation of the actual rate of
glaucoma progression.

Conversely, for glaucoma patients who
had cataract surgery during follow-up,
improvement in media clarity masked
glaucoma progression when assessed
by the MD. It did not happen when
assessment was performed with the
VFI. The VFI also provides an estimate
of the visual field loss that will occur

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Figure 3: Progression of visual field damage Trend Analysis. Other than Humphrey Visual Field
analyser, Octopus (Haag-Streit
Figure 4: Progression analysis tools available in octopus perimeters. International, Koeniz, Switzerland) is
a commonly used perimeter. The Eye
in the next 5 years, assuming that the number of years that a patient has before Suite Progression Analysis function
same rate of progression is maintained. advancing to blindness. A summary of the Octopus includes three types
This is valuable for the treating of the progression of visual field loss of progression analysis: Global Trend
ophthalmologist as it estimates the analysis is presented in (Figure3). Analysis (GTA), (Corrected) Cluster
Trend Analysis (CTA and CCTA), and
Polar Trend Analysis (PTA). The Global
Progression Analysis measures the
change in the global indices, namely
Mean Defect (MD), Diffuse Defect
(DD), Local Defect (LD) and square
Root of Loss Variance (sLV) over time.
It also provides information about the
rate of change in dB/year and on the
local, diffuse or combined nature of
progression. The Cluster Trend Analysis
assesses cluster-specific progression
within ten nerve fiber bundle regions
separately, which is particularly useful
in glaucoma. Furthermore, the Polar
Trend Analysis facilitates the detection
of spatially corresponding structural
and visual field changes (Figure 4).

To summarize, both HFA and Octopus
perimeters can be used effectively
to detect progression. It is crucial to
measure the rate of progression (change
per year in dB) to make decisions
about potential interventions before
significant visual field loss develops.

References
1. Kim J, Dally LG, Ederer F, Gaasterland

DE, VanVeldhuisen PC, Blackwell B,
Sullivan EK, Prum B, Shafranov G, Beck
A, Spaeth GL; AGIS Investigators. The
Advanced Glaucoma Intervention Study
(AGIS). Distinguishing progression of
glaucoma from visual field fluctuations.
Ophthalmology 2004 111(11): 2109-16.
2. Boden C, Blumenthal EZ, Pascual J,
McEwan G, Weinreb RN, Medeiros F,
Sample PA. Patterns of glaucomatous
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Ophthalmol 2004 138(6): 1029-36.
3. Chauhan BC, Garway-Heath DF, Gof\i
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