SURGICALPEARLS
Surgical Pearls in Squint Surgery
Harbansh Lal MS, Ekta Jain MS Anita Sethi MD, FRCS, Piyush Kapur DNB, MNAMS
The primary goal of strabismus surgery is to eliminate incision gives less post-operative conjunctival scarring and
the relative deviation of the visual axis. Surgery is a better cosmesis.
performed for functional reasons to create comfortable
single binocular vision or if this cannot be accomplished, The conjunctival tenon’s complex are grasped with 2
to re-establish a normal ocular configuration. The purpose toothed forceps (fig.2) one by the surgeon and the second
of the surgery should be to correct the static angle of the by the assistant. The conjunctival tissue is grasped 2-3mm
strabismus and not the dynamic angle. above or below the horizontal pupillary line, about 2mm
lateral to the limbus. A radial cut is made in this tented
There are two ways by which we can alter the action conjunctiva so that both the conjunctiva and the tenons
of any muscle by weakening (recession) or by strengthening are cut to expose sclera underneath (fig.3). The sub-tenon
(resection) or the two procedures can be combined. plane is identified and conjunctival tenons complex is
dissected from sclera by inserting the conjunctival scissors
The variability of surgical results is as a result of in the subtenon space and continuing blunt dissection.
numerous factors: the sensory state of the patient, the
operative technique, the manner in which the muscle is Once tenon’s and sclera are separated, the conjunctiva
exposed, how thoroughly it is freed, whether the check is cut smoothly at the limbus so that no frill of the tissue
ligaments are severed, the placement of sutures the, remains attached to the limbus. To accomplish this one
occurrence of intra-operative bleeding, the tendency to
form adhesions and scarring, the state of conjunctival Fig.1: Putting the fixation sutures with 6-0 silk
elasticity and anatomical variations of muscle insertions.
There are some fectors influencing surgical outcomes.
After deciding the muscle, the procedure and the
amount you want to operate in a particular case the eye is
prepaired for surgery.
The globe and its adnexa can be completely
aneasthetized locally by peribulbar block. Children and
apprehensive or nervous adult patients should be given a
general aneasthetic. After aneasthesia we clean scrub and
drape the eye as we do for other ocular procedures. After
placing the speculum we fix the globe. We take clear corneal
half thickness bites near the limbus with 6-0 silk on
spatulated needle. For horizontal muscles at 12 & 6 o’clock
and for vertical muscles at 9 and 3 o’clock (Fig.1).
Exposure of the muscle
There are different methods to expose the muscle; one
being limbal and the other para-limbal, both have their
own advantages and disadvantages.
We prefer the limbal approach as in this method we
are able to grasp the conjunctiva and the Tenons together
because of their adherence to each other at the limbus, and
a good clean sub-tenon’s dissection is possible. As we don’t
cut the conjunctiva in between, blood vessels don’t get
injured and their continuity remains maintained. So limbal
Department of Ophthalmology Fig.2: Tenting the conjunctiva with forceps held paralled to limbus
Sir Ganga Ram Hospital,
New Delhi 1 February, 2007
DOS Times - Vol. 12, No. 8
Fig.3: Giving radial niche in the conjunctiva near the limbus approximately 2-3 mm above the
Fig.4: Muscle hooked horizontal pupillary line (almost
1mm above the superior horizontal
insertion of the horizontal muscles).
A radial cut is made at the
superior edge of the conjunctival flap
(fig.3) extending almost 6-7mm
backward going almost upto the
insertion of the horizontal muscles.
The assistant lifts the
conjunctival flap up with the help of
2 forceps and the sub-tenon plane is
identified to carry out the dissection in this plane a little
beyond the muscle insertion.
Once the muscle insertion is identified, a small window
is cut open in the intermuscular septum, at inferior border
of the muscle at the insertion side, to expose the sclera
underneath. This is essential to avoid any undue damage
to the muscle sheath. After seeing the sclera smoothly
pass the muscle hook under the muscle. Now pull the hook
up and away from the centre (fig.4). Gently separate the
sheath at the opposite end of the muscle to anchor it on the
muscle hook without actually damaging the muscle sheath.
The muscle is gently separated from the surrounding
tissues by blunt dissection using a swab stick (fig.5). When
you pass the muscle hook by these methods (after exposing
the sclera) usually you get the whole muscle at once. But if
you are not sure about it then rehook the muscle by passing
a second muscle hook from other side and removing the
first hook. This ensures complete hooking of muscle fibres.
Once the muscle and its insertion has been isolated
and cleaned the required surgical procedure can be
performed.
Fig.5: Rectus muslce freed with blunt dissection Recession
blade of the conjunctival scissor is passed under the During the recession operation, we always cut the
conjunctiva such that the sharp edge is facing the check ligaments. During surgery on the SR accidental
conjunctiva, the tissue is made taut by pulling the inclusion of the SO tendon on the muscle hook must be
conjunctiva away from the limbus and with the scissor avoided. When recessing IR muscle one should take special
blade pushing the conjunctiva tenons complex towards care to dissect the intermuscular membrane and all facial
the center of the cornea, (fig.3) we move the external blades attachments between IR and Lockwood’s ligament.
to cut the conjunctiva smoothly with out leaving any tissue
attached at the limbus. The conjunctiva is cut Now we pass two single armed 6-0 vicryl suture from
the muscle close to its insertion site (fig.6a&6b). While you
are passing the suture assistant should keep the muscle
taut and convex by pulling the hook up and away from the
centre, so that you take only muscle fibers during passing
the suture not the sclera. We make two loops first loop is of
50% depth of the muscle and it is 1-1.5mm away from the
muscle border second loop is 90% deep and close to muscle
border (whip stitch). After making the second loop we pass
the needle twice from the first loop as shown in the figure.
Now we tie the suture. This locking of muscles gives a
good grip of the muscle with out crushing the fibers. This
February, 2007 2 DOS Times - Vol. 12, No. 8
Fig.6a: Passing 6-0 vicryl sutures Fig.6b: Whip Stitch (side view) lower threads and stitch carefully
upper thread to upper and lower
threads to lower marked sites. While
re-attaching the muscle to the sclera
the needle should be horizontal and
should not be tilted. It is while passed
50% depth of the sclera so that it is
visible through out passing from the
sclera. Muscle width and contour
should be maintained during re-
attaching the muscle at its new
insertion site.
Fig.7: Marking the muscle with marking pen Resection
For resection all the points for marking of the muscle
also helps to maintain the width of the muscle.
We pass the vicryl suture as explained above from are same. After marking the muscle we pass the 6-0 vicryl
in the similar way as we explained for recession of the
both (upper and lower) ends of the muscle. muscle. After locking the muscle we cut it carefully at the
marked site preserving all threads (fig.8). Some people use
Marking of the sclera (fig.7) muscle clamps, but we don’t find any added advantage of
1. Eye should be rotated properly, there should not be this. After cutting the muscle let the muscle hang freely
without being twisted.
any vertical rotation for horizontal muscles and vice
versa so that there is not involuntary vertical Disinsert the remaining part of the muscle from the
displacement of the horizontal muscles while insertion site. The stump of the muscle is pulled and cut
reinserting them. sweep from the scleral bed without leaving any fibers, as
2. Muscle should not be stretched. Sclera should be bared these may give a poor cosmetic scar latter. Now attach the
at the point of marking. muscle to the sclera (fig.9).
3. You may use gentian violet or marker or a simple
indentation mark of the caliper. Separate the threads carefully and attached the muscle
4. You should mark for both upper and lower ends of the to its insertion site. Take 50% deep sclera bites. The needle
muscle. should pass perpendidul. After stitching the upper and
Now with the hook in place stretch the muscle by lower ends take the needle of both ends one by one pass
pulling the muscle above the sclera. So that the muscle lies then it from the middle of the muscle to attach the central
1-2mm above the sclera. Disinsert the muscle from its part of the muscle (fig.10). Here again you should try to
insertion site with straight scissors, as close to the insertion keep maintain the width and contain of muscle insertion.
as possible. Usually we don’t get much bleeding but if you
feel any need you may use wet field cautery. Fig.8: Muscles being cut after passing the anchoring sutures
Look for the marked sites. Separate both upper and
DOS Times - Vol. 12, No. 8 3 February, 2007
Fig.9: Stump of the muslce being cut from the insertion site Fig.10: Central sutures being placed close to the central muscle belly
Closure Rest conjunctiva we suture with single knot with
double loop. They may fall off their own or you may need
Only the conjunctiva is sutured First pass the suture to just pull one end while removing them.
(6-0 site) from free the end of conjunctiva then to fixed end.
First knot is of two loop and second is of single loop. It One should take care to see that tenon’s should be in
anchor the conjunctiva well. The suture should be cut side the conjunctiva. It should not protrude from any point
adequate length neither too long and now too short. if it is protruding you should excise it. There should be ½
mm bared area from the limbus so that the conjunctiva
does not over ride the cornea.
February, 2007 4 DOS Times - Vol. 12, No. 8
MEDICALOPHTHALMOLOGY
Crosslinking Treatment for Progressive Keratoconus
Namrata Sharma1 MD, Vishal Jhanji2, MD, Jeewan S. Titiyal 2, MD
Keratoconus is a common condition that affects about collagen fibrils (ie, cross-linking) to produce a general
1 in 2000 of the population. It primarily affects the young, strengthening of the cornea (Figure 1). Biomechanical
presenting in adolescence with impaired vision. In many measurements have shown an increase in corneal rigidity
cases the condition progresses and the cornea becomes of 328.9% in human corneas after crosslinking.
ectatic, especially inferiorly. These cases can initially be
managed with the help of spectacles and rigid contact Indications
lenses but a significant number of eyes become intolerant The indications of this therapeutic intervention are
to contact lenses and require keratoplasty. Keratoplasty
though has a good success rate in cases of keratoconus, but where a biomechanical stabilization of the cornea is
is associated with the inherent risks of an intraocular required like keratoconus, corneal melting and iatrogenic
surgery. Also, the scarcity of donor corneal tissue in keratectasia. There are other indications for C3- riboflavin
developing parts of the world compounds the problem. when combined with other surgical procedures. They
include intracorneal rings, conductive keratoplasty, laser
It is known that keratoconus is very rare in diabetes thermokeratoplasty and orthokeratoplasty.
mellitus due to collagen crosslinking by so-called advanced
glycation endproducts (AGEs) and also rare at higher age Preoperative work up
due to age-related crosslinking. In view of this corneal cross The UCVA, BSCVA, manifest refraction spherical
linking with riboflavin (vitamin B2) was developed by
Theo Seiler, in Zurich, Switzerland. equivalent, IOP, pachymetry, topography and difference
maps, K values and enhanced corneal compensation
Corneal collagen cross-linking riboflavin is a non- should be documented pre-operatively.
invasive procedure which strengthens the weak corneal
structure in keratoconus. This technique works by increasing Exclusion criteria
collagen cross-linking, which are the natural “anchors” within the Aphakic eyes and eyes in which the pachymetry
cornea. which prevent the cornea from bulging out and
becoming steep and irregular. values are less than 400 ìm should be excluded.
It is a 30-minute, OPD procedure. During the treatment, Preparation of Riboflavin eyedrops
custom-made riboflavin eyedrops are applied to the cornea, Riboflavin is prepared as a 0.1% solution using 0.3 ml
which is then activated by a UVA light. This increases the
amount of collagen cross-linking in the cornea and Riboflavin with 0.7 ml of 0.9% saline and 250 mg of Dextran.
strengthens the cornea. The technique uses and riboflavin
to create new bonds between the adjacent collagen
molecules so that the cornea is about one-and-a-half times
thicker and less malleable.
Mechanism of action
Application of riboflavin on the cornea along with
penetration for approximately 200 ìm and irradiation of
the riboflavin molecules through UVA leads to loss of the
internal chemical balance of the riboflavin molecules,
producing oxygen free radicals. The riboflavin molecule
becomes unstable and stabilizes only when it is linked to
two collagen fibrils. A cross bridge is created between the
1. Moorfields Eye Hospital NHS Foundation Trust Fig.1: Collagen Crosslinking treatment for keratoconus
162 City Road,London, United Kingdom
2. Rajendra Prasad Centre for Ophthalmic Sciences
All India Institute of Medical Sciences, New Delhi, India
DOS Times - Vol. 12, No. 8 5 February, 2007
unless it is essential (i.e., whenever the penetration of
riboflavin appears insufficient). The eye is treated with
proparacaine 0.5% for d”30 minutes before UVA exposure
(ie, approximately two drops every 5 minutes). Riboflavin
is then applied on the cornea for d”25 minutes before
irradiation and penetrates in the stroma for d”200 ìm. The
riboflavin is then activated by a 30-minute exposure to
the UVA light using tw o calibrated UVA LED diodes (ie,
370 nm fluence at 3 mW/cm2) to the central 8 mm of the
cornea. The riboflavin solution must be reapplied on the
cornea every 3-5 minutes during the UVA irradiation
(Figure 2).
This is followed by overnight patching of the eye. The
postoperative treatment consists of topical antibiotics and
topical corticosteroids.
Fig.2: Mechanism of Collagen cross linking Post-operative follow up
The drops are administered topically to the surface of the Thin stromal demarcation line is visible at a depth of
cornea (6 drops over 30 minutes) during the treatment approximately 300 microm over the whole cornea after X-
itself. linking treatment which results from differences in the
refractive index and/or reflection properties of untreated
Technique versus X-linked corneal stroma and represents an effective
The epithelium is not debrided during the procedure tool to biomicroscopically easily monitor the depth of
effective X-linking treatment in keratoconus1.
It has been demonstrated by Mazzotta et al by the
confocal microscopy that the corneal re-innervation is
restored after riboflavin-UVA-induced collagen cross-
Table : Results Of Collagen Cross linking In Keratoconus
Author/year Number of eyes/Follow up Results
Wollensak et al3/2003 22 eyes/3 years In all treated eyes, the progression of keratoconus was
stopped (‘freezing’). In 16 eyes there was a slight reversal
Sandner et al 4/2004 60 eyes/5 years and flattening of the keratoconus by 2 diopters. BCVA
improved slightly in 15 eyes
Braun et al5/2005 27 eyes/
No patient had further progression of keratectasia. In 31 eyes
Caporossi et al6/2006 10 eyes/6 months postoperative regression by2.87 D was observed. BCVA
improved slightly by 1.4 lines.
Chan et al 7 /2007 Two groups: Group I
Stabilization of keratoconus in all and regression by 2D in 12
intacs only Group II eyes occured. An increased corneal rigidity in vivo using a
intacs with C3R contact ultrasonic device was demonstrated.
Refractive results showed a reduction of about 2.5 D in mean
SEQ, topographically confirmed by reduction in mean K.
Results of surface aberrometric analysis showed
improvement in morphologic symmetry with a significant
reduction in comatic aberrations.
Significantly greater decrease in cylinder ,Reduction of
keratometry and in Lower -Upper ratio on topography in
the Intacs with C3-R group as compared to intacs only group
February, 2007 6 DOS Times - Vol. 12, No. 8
linking directly in vivo in humans after 6 months of of 81 mW/cm2, which is not reached with the standard
treatment2. treatment protocol.
Results In summary, to avoid danger for the endothelium, lens
The results of the various studies published in or retina it is mandatory in each patient to perform
preoperative pachymetry to exclude extended areas with
literature are summarized in table 1 less than 400 μm stromal thickness, and to check the UVA
irradiance exactly using a UVA-meter.
Risks and side effects References
UV light in general represents a potential danger to 1 . Seiler T, Hafezi F. Corneal cross-linking-induced stromal
the human eye.In the crosslinking treatment, just a small demarcation line.Cornea. 2006 Oct;25(9):1057-9.
peak-like sector of the UVA-spectrum (370 nm) is used.
However, the UVA absorption in the cornea is increased 2 . Mazzotta C, Traversi C, Baiocchi S, Sergio P, Caporossi T,
massively during the crosslinking procedure due to the
photosensitizer riboflavin, resulting in a UVA- Caporossi A. Conservative treatment of keratoconus by riboflavin-
transmission of only 7% across the cornea . uva-induced cross-linking of corneal collagen: qualitative
In rabbits a cytotoxic level for endothelium was found investigation.Eur J Ophthalmol. 2006 Jul-Aug;16(4):530-5.
to be 0.36 mW/cm2 which would be reached in human 3 . Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-A-induced
corneas with a stromal thickness of less than 400 μm with
the standard treatment parameters [25,26]. In the normal collagen crosslinking for the treatment of keratoconus. Am J
eye, UVA is absorbed mainly by the crystalline lens, which
also contains endogenous riboflavin and other Ophthalmol 2003; 135:620–627
photosensitizers leading to crosslinking of crystallins and 4 . Sandner D, Spörl E, Kohlhaas M, et al. Collagen crosslinking by
sometimes cataract in the long term. With the current
treatment parameters the lens only receives 0.65 J/cm2 combined riboflavin/ultraviolet-A (UVA) treatment can stop the
which is far below the cataractogenous level of 70 J/cm2. In progression of keratoconus [abstract]. Invest Ophthalmol Vis Sci
the rhesus monkey, retinal damage with complete loss of
the photoreceptor layer was reported at a threshold level 2004; 45:E-abstract 2887.
5 . Braun E, Kanellopoulos J, Pe L, Jankov M. Riboflavin/ultraviolet
A-induced collagen cross-linking in the management of
keratoconus [abstract]. Invest Ophthalmol Vis Sci 2005; 46:4964.
6 . Caporossi A, Baiocchi S, Mazzotta C, Traversi C, Caporossi T.
Parasurgical therapy for keratoconus by riboflavin-ultraviolet type
A rays induced cross-linking of corneal collagen: preliminary
refractive results in an Italian study.
7 . J Cataract Refract Surg. 2006 May;32(5):837-45. Chan CC, Sharma
M, Wachler BS. Effect of inferior-segment Intacs with and without
C3-R on keratoconus.J Cataract Refract Surg. 2007 Jan;33(1):75-
80.
DOS Times - Vol. 12, No. 8 7 February, 2007
MEDICALOPHTHALMOLOGY
Corneal Microsporidiosis
M.Vanathi MD, Sanjay Kai MD , Anita Panda MD
Microsporidia are being increasingly recognized as fully formed spore measures about 2.5x1.5 microns.The
opportunistic infectious pathogen in immuno- cell eventually ruptures to continue the cycle and further
compromised patients. They can cause intenstinal, sinus, destruction of the host tissue.
renal, pulmonary, and ocular disease. The first case report
of corneal microsporidiosis was published in 19731. Clinical features
Two other case reports involving the corneal stroma Only two species Nosema andEncephalitozoon , are known
were reported in 1981 and 1990 by Pinnolis et al2and Davis to cause ocular infections.
et al3, respectiv ely. A case series of five patients of
Microsporidial stromal keratitis has recently been reported Two clinical presentations of ocular Microsporidiosis
from south India4. are observed :a corneal stromal keratitis, which occurs in
immunocompetent patients and is commonly caused by
Microscopic features Nosema corneum.13 and a superficial punctuate
keratoconjuctivitis occurring in acquired immune
Microsporidia are small (3.5-5.0 μm in length by 2.0- deficiency syndrome (AIDS) patients or in contact lens
3.0μm in width), oval obligate intracellular eukaryotic wearers mostly caused by genus Encephalitozoon. However
protozoan parasites that belong to phylum Microspora. recent reports suggest that keratoconjuctivitis can also
More than 100 species have classified into approximately occur in immunocompetent individuals. Ocular
100 genera, and atleast 13 species have been reported to Microsporidiosis in immuno-competent patients can
infect mammals.5-8 Phylogenetically Microsporidia are mimic as herpes simplex virus keratitis. The patients
early eukaryotic organisms because they have have a true usually present with history of recurrent episodes of pain,
nucleus, possess prokaryotic like ribosome, and lack redness, watering, photophobia and dimunition of vision.
mitochondria.7Seven genera (Enterocytozoon species, Brachiola
species, Encephalitozoon species, Pleistophora species, Nosema species, Some patient may be misdiagnosed as case of herpes
Vittaforma species and Trachipleistophora species) as well as stromal keratitis and get treated with topical steroids and
unclassified microsporidia (collectively refered to as antivirals. On examination patient may present with lid
Microsporidium) have been associated with human edema, conjuctival congestion. Corneal lesions are usually
disease involving immunocompromised patients.5-8 mid to deep stromal infilterates with surrounding stromal
edema. The overlying epithelium may be intact with edema
Epidemiology and risk factors or in some cases there can be a epithelial defect.There can
be exudates on the endothelium.
Microspoidia are increasingly recognized as
opportunistic infectious pathogen in immuno- Diagnosis
compromised patients. The source of infection for human
and routes of transmission are unknown ; however they Microsporidia are small, obligate intracellular
are thought to be either orofaecal, resulting from direct parasites that produce infective spores. They are fastidious
inoculation, or occurring after trauma1. Direct inoculation organisms that are difficult to culture. The organism can
may occur with close contacts with domestic animals such be isolated using special tissue culture techniques, which
as cats and birds.9,10 ; it may also spread from other infected are available only in a few specialized laboratories, and
persons.11,12 The normal life cycle of microsporidia hence routine microbiological diagnosis might be
comprises of invasion of the spore into the human host cell difficult.11,14
followed by discharge of the contents into the cytoplasm
.Within the cell the sporoblast divides by binary fission to Alcohol- fixed cytologic samples of scrapings from the
form scizont with 2-6 nuclei, which split into unicellular conjuctiva, corneal epithelium, or both or biopsy‘
meronts .The meronts then secrete a rigid capsule and the specimens have proven very useful for demonstrating
microsporidial blastospores.3,15 Often conjuctival scrapings
Cornea Services alone provide a satisfactory specimen for cytologic
Dr Rajendra Prasad Centre for Ophthalmic Sciences, diagnosis in microsporidial epithelial punctuate
All India Institute of Medical Sciences, New Delhi 110029 keratoconjuctivitis. Cytologic findings demonstrate small,
oval organisms within the epithelial cells, stromal
keratocytes, and histiocytes as well as free extrecellular
February, 2007 8 DOS Times - Vol. 12, No. 8
structures.2,3,16,17,18 Thesespores have uniform oval shape well as the use of topical steroids or bandage contact lenses
and are nonbudding, which help to differentiate them from
bacteria and yeasts.12,19 The spores stains strongly with in such patients because they may result in secondary
gram stain.16,17,20,21 Giemsa stains have also been successfully infection and penentration of the organisms into the deeper
used to demonstrate microsporidial spores.1,12,16,17
Occasionally, these spores stain poorly or not at all with stroma.
routine stains (hematoxylin-eosin or the Papanicolaou
methods), with the organism being easily overlooked in Recents reports have documented the successful
biopsy specimens or cytologic preparations.19,22
treatment of Microsporidial superficial keratoconjuctivitis
Definitive genus identification of microsporidial ocular with topical fumagillin21,24-28 Fumagillin is a naturally
infections requires examination of corneal or conjuctival
biopsy specimens, or both, by electron microscopy to secreted water-insoluble antibiotic of Aspergillus fumigatus
demonstrate the number of coils of the filament.2,16,17,18, 20,21,22 and is noted to posess an inhibitory effect on some
The differentiation of Nosema species intenstinal protozoa.27 Fumagillin bicyclohexylammonium
salt is water soluble form of fumagillin used commercially.
from Encephalitozoon is based on several electron
microscopic features.First Nosema are larger than The mechanism of action of fumagillin are not clearly
Encephalitozoon (Nosema organisms measures understood but the preliminary data suggest that the drug
approximately 3.5- 5.0μm in length versus 2.0-3.0μm in
length for Encephalitozoon organisms): Second , the absence may alter DNA content or inhibit RNA synthesis in the
of a parasitophorous vacuole surrounding the organism organism29,30.Some authors have also suggested the role of
within the host cell is more consistent with Nosema. Third,
the coils of the filament range from 11 to 13 in Nosema oral Albendazole in combination with topical fumagillin.In
versus 4 to 7 in Encephalitozoon. case where the medical treatment fails penentrating
Treatment keratoplasty is recommended rather than lamellar graft
to treat deep stromal microsporidiosis to avoid any chance
At present there is no known definitive medical
treatment of deep microsporidial corneal stromal of reccurence in the lamellar bed.
infections. Some previous reports have suggested that
treatment with topical propamidine isethionate In conclusion, microsporidial ocular infections should
0.1%(Brolene)22,23 or systemic itraconazole16 may be effective
against microsporidial superficial keratoconjuctivitis . Yee be considered in the differential diagnosis of culture-
et al16 reported subjective improvement with debulking negative stromal keratitis or keratoconjuctivitis refractory
and a combination of topical neomycin, bacitracin, and
polymyxin B antibiotics in a patient with bilateral to conventional medical treatment.
epithelial keratopathy caused by Encephalitozoon, however
complete resolution was achieved only after References
administration of oral itraconazole.
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3 Davis RM, Font RL, Keisler, MS, Shadduck JA. Corneal
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4 Geeta K Vemuganti et al. Is microsporidiosis keratitis an emerging
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6 Shadduck JA. Human microsporidiosis and AIDS. Rev Infect Dis
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7 Didier ES, Snowden KF, Shadduck JA. Biology of microsporidian
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8 Weber R, Bryan RT , Schwartz DA, Ow en RL. Human
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9 Botha WS, van Dellen AF, Stew art CG. Canine
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1 0 Gannon J. A survey of Encephalitozoon cuniculi in laboratory
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1 2 Schwartz DA, Bryan RT, Visvesv ara GS. Diagnosti approaches
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Microbiol 1994; 41:59S-60S.
1 3 Silveria H, Canning EU. Vittaforma corneae n. comb. For the
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Microbiol 1995; 42:158-65.
14 Didier ES, Didier PJ, Friedberg DN, et al. Isolation and
characterization of a new human microsporidian, encephalitozoon
DOS Times - Vol. 12, No. 8 9 February, 2007
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92. 2 4 Roseberger DF, Serdarevic ON, Erlandson RA, et al. Successful
1 6 Yee RW, Tio FO, Martinez JA, et al. Resolution of microsporidial treatment of microsporidial keratoconjunctivitis with topical
epithelial keratopathy in a patient with AIDS. Ophthalmology fumagillin in patient with AIDS. Cornea 1993;12:261-5.
1991; 98:196-201. 25 Mccowen MC, Callender ME, Lawlis JF Jr Fumagillin a new
1 7 Friedberg DN, Stenson SM, Orienstein JM, et al. Microsporidial antibiotic with amebicidal properties. Science 1951; 113:202-3.
keratoconjunctivitis.in acquired immunodeficiency syndrome 2 6 Shadduck JA. Effect of fumagillin on in vitro multiplication of
Arch Ophthalmol 1990;108:504-8. Encephalitozoon cuniculi
1 8 Weber R, Kuster H, Visv esvara GS, et al. Disseminated J Protozool 1980; 27:202-8.
microsporidiosis due to encephalitozoon hellum : Pulmonary 2 7 Killough JH, Magill GB, Smith RC. The treatment of amebiasis
colonization , microhematuria, and mild conjunctivitis in patient with fumagillin. Science 1952; 115:70.
with AIDS. Clin Infect Dis 1993; 17:415-9. 2 8 Katzneslon H, Jamieson CA. Control of nosema disease of honey
19 Schwartz DA, Sobottka I, Leitch GJ et al. Pathology of bees with fumagillin. Science 1952; 115:70-1.
microsporidiosis.Emerging parasitic infections in patients with the 2 9 Hartwig A, Przelecka A. Nucleic acid in intenstine of Apis mellifica
AIDS. Arch Pathol Lab Med 1996; 120:173-88. infected with Nosema apis and treated with fumagillin
2 0 Lowder CY Meister M, McMahon JT, et al. Microsporidia infection DCH.:cytochemical and autoradiographic studies. J Invertebr
of the cornea in a man seropostive for HIV virus. Am J Ophthalmol Pathol 1971; 18:331-6.
1990; 109:242-4. 3 0 Jaronski ST. Cytochemical evidence for RNA synthesis inhibition
2 1 Diesenhouse MC, Wilson LA, Corrent GF, et al. Treatment of by fumagillin. J Antibiot 1972; 25:327-31.
microsporidial keratoconjunctivitis with topical fumagillin. Am J
February, 2007 10 DOS Times - Vol. 12, No. 8
MEDICALOPHTHALMOLOGY
Diplopia
Nidhi Gupta MBBS, Kanak Tyagi DOMS, DNB, Gaurav Kakkar MS
It is Greek work which means double vision. It is 4. Refractive - Bifocal glasses
caused due to the breakdown in the fusional capacity of Contact lens
the binocular system.
5. Retinal Maculopathies
The etiology of diplopia varies from simple 6. Drug induced
astigmatism to life threatening intra cranial anomalies.
So, the clinician should be aware of this minor symptom. Diagnosis of Diplopia
The value of a good history should never be
CAUSES OF
I. Monocular Diplopia underestimated in the diagnosis of diplopa. A complete
description of diplopia in terms of onset, progression,
Diplopia persists on occlusion of one eye. severity, duration, location, variability can help in making
1. Refractive - Astigmatism diagnosis.
1. History & Symptoms
Anisometropia Previous ocular history of occlusion, prismatic lenses.
2. Corneal - Pterygium, Corneal Scars, Keratoconus General health - weakness & fatigue myasthenia gravis
3. Lenticular - Dislocated lens, Ectopia lentis
4. Iridectomy or Iridotomy Multiple sclerosis
5. Dry Eye D.M. & HTN
6. Retinal Maculopathy Injury & Surgery
7. Cortical Diplopia Family history - Hypermetropia
8. Psychogenic Ocular motor disorder
2. Observations
II. Binocular Diplopia Abnormal Head Posture
Occurs when both the eyes work together and resolved Lid Position - Ptosis
Lid Retraction
by occlusion of either eye. Majority of patients of diplopia 3. Monocular Test - Monocular occlusion
are due to binocular causes VA with & without pinhole to rule out refractive errors
Amslers chart for macular disorders
1. Physiological
2. Concomitant- decompensating heterophoria(angle of
deviation is same in different directions of gaze)
3. Inconcomitant
(i) Myogenic - thyroid ophthalmopathy
(ii) Neuromuscular junction disorders - myasthenia,
(iii) Paralytic - Nuclear/Infranuclear
- Supranuclear lesions are not normally associated
with diplopia
(iv) Restrictive -blow out fractures, orbital tumours,
Browns syndrome
Venu Eye Institute & Research Centre, 11 February, 2007
1/31, Sheikh Sarai, Phase-2,
New Delhi-17
DOS Times - Vol. 12, No. 8
9. Forced duction test
10. Lees Screen
11. Diplopia charting -This can be a very useful tool for
differential diagnosis of incomitancy.A vertical bar of light
is viewed through red and green goggles at a fixed distance
of 50 cm from the eye. The light bar is moved into each
direction of gaze and the patient describes the image
separation and .that can be measured.
By convention the red filter is placed in front of right
eye. The symbol $ is used to describe the two lines as
superimposed. When interpreting the diplopia chart it
should always be remembered that the most distal image
belongs to the under acting eye. The position of image is
the reverse of the position of the eye.
Investigations:- These are indicated in cases of injury,
suspected intracranial mass or if any paralytic squint not
showing improvement in 3 consequent visits
1. CT Scan and MRI Skull and orbit
2. Tensilon Test for myasthenia gravis
Consultations:-
Diabetologist - in case of isolated cranial nerve weakness
Endocrinologist - thyroid disorders
ENT Specialist - Sinus diseases & blow out fractures
Neurologist - cranial nerve palsy
Case of acquired limited elevation RE complaint of Diplopia. CT Medical Care:-
scan showing Chordoma/ Nasopharyngioma? 1. Patching One Eye
2. Fresnel Prism
4. Cover Test 3. Treatment of myasthenia gravis
5. Ocular Motility - Ductions & versions
6. Near point of convergence Prognosis:-
7. Measurment of angle of deviation 1. Neurological causes of diplopia can have serious
Prism cover test
Maddox double rod test( torsional diplopia) consequences and in the case of primary or secondary
8. Hess Chart tumors, have a dire prognosis.
2. Patients with diabetic mononeuritis multiplex recover
spontaneously in approx. 6 wks.
3. Blow-out fractures have a variable prognosis
depending on the amount of tissue damage.
4. Optical causes are amenable to repair
February, 2007 12 DOS Times - Vol. 12, No. 8
MEDICALOPHTHALMOLOGY
Intermittent Exotropia: Evaluation and Management
Sandeep Buttan MS, Archana Gupta DNB, Manish Sharma MS, Suma Ganesh MS
Exodeviation or divergent squint is one of the most Clinical presentation:
frequently encountered forms of binocular dysfunctions
in any ophthalmic practice. A transient small exotropia IDS most commonly presents in early childhood,
may be seen in as many as 60 – 70 % normal newborns, between 6 – 12 months of age. It is extremely rare to have
which resolves by 4 – 6 months. an onset after 4 years.
Intermittent exotropia (IDS) is a relatively common Usually a manifest divergent squint of either eye is
presentation of exodeviation in which orthophoria is noticed by the parents when the child is tired or ill or
maintained by fusion during most of the time but it becomes during daydreaming. An increase in the amount of the
manifest spontaneously, unlike latent squint (phoria) which squint may also be reported when the child is looking at a
manifests only when fusion is disrupted. distant object.
IDS constitutes about one fifth of all strabismus and Due to its unique features there are very little visual
nearly 50 – 90 % of all cases of exotropia. symptoms, some children may however complain of
transient diplopia or asthenopia especially after prolonged
The unique features of IDS that make its management reading.
controversial are
1. Variable angle of deviation Diplophotophobia, or closure of one eye in bright light is
2. Unpredictable course of progression (i.e. deterioration a very common symptom in IDS. It occurs as an attempt to
of control) avoid diplopia caused by sudden disruption of fusion due
3. Good binocularity (for near till late) to bright light.
4. Rarity of amblyopia or ARC (abnormal retinal
correspondence) Classification
Progression of IDS Burian has classified IDS in to 4 types based on
Although IDS has been postulated to be a precursor of measurements of the distance and near deviation.
manifest exodeviation, the natural course of this 1. Basic type: distance deviation and near deviation are
progression remains obscure. Calhounz has described four within 10 PD of each other.
phases in the natural history of IDS (Table 1)
2. Divergence excess type: distance measurement 10 PD or
Etiology greater than the near deviation.
The first etiological concept regarding exodeviations
3. Convergence insufficiency type: near deviation 10 PD
was proposed by Duane who believed it to be a result of greater than the distance.
innervational imbalance (Innervational theory) between
active convergence and divergence mechanisms. 4. Simulated or pseudo divergence excess type: the near deviation
is less than the distance deviation but it increases to within
Ever since various theories have been put forward, 10 PD of distance deviation after 30 – 60 minutes of
the most notable being monocular occlusion
1. Mechanical theory. (Bielchowsky)
2. Theory of Defective fusion (Worth) Kushner has further modified this classification by
3. Hemiretinal suppression (Knapp and Jampolsky). taking into account the relationship between
4. Uncorrected refractive errors (Donders) accommodative convergence and accommodation (AC/A
ratio). He introduced two new groups Pseudo divergence
Department of Pediatric Ophthalmology & Strabismus with tenacious proximal fusion (near deviation increase after
Dr. Shroff Charity Eye Hospital, 60 minutes of monocular occlusion) anddivergence with High
Ansari Road, Darya Ganj, AC/A ratio.
New Delhi
Evaluation of IDS
Intermittent exotropia is a management dilemma for
the strabismologist. Any intervention must endeavor to
improve unacceptable mal alignment and poor BSV for
distance whilst preserving or improving BSV for near.
DOS Times - Vol. 12, No. 8 13 February, 2007
Phase Deviation Sensory 3. Stereo-acuity: It has been shown
I that stereoacuity (mainly for
II Exophoria at distance, orthophoria at near Asymptomatic distance) is a objective indicator of
both control of the deviation and
III Intermittent exotropia for distance, Symptomatic for deterioration of fusion. The distance
orthophoria/ exophoria at near distance stereoacuity can be assessed using
the Random dot E test or the Mentor
Exotropia for distance, exophoria or BV for near, B- Vat tests.
intermittent exotropia at near. suppression scotoma
for distance
IV Exotropia at distance as well as near Lack of binocularity. Management options
The most important factors that influence the mode of Due to its unique characters and
treatment in IDS are the magnitude and type of the unpredictable progression, the management of IDS still
deviation and the level of the corrective fusional control. remains controversial.
Measurement of the deviation The treatment options are broadly divided into two
heads, conservative (non-surgical) and surgical.
Certain special considerations must be highlighted
while measuring the angle of deviation in IDS. Non-surgical modalities (Passive vision therapy):
1. Prolonged alternate cover test: to maximally suspend the The goal of Vision therapy in IDS is to improve the
tonic fusional convergence during the ACT the occluder neuro-physiological vergence control mechanism so as to
must be placed in front of either eye for a sufficient duration decrease the frequency of the manifest phases and to
and alternated swiftly. prevent (or reverse) the progression from latent to constant
squint.
2. Patch Test: Mono ocular occlusion for 30 – 60 minutes
differentiates true and pseudo divergence excess type of The various non-surgical therapies include
IDS when the near deviation is less than the distance
exodeviation. 1. Correction of Refractive errors (Any uncorrected Myopia,
astigmatism or high Hyperopia)
3. High AC/A ratio (Lens gradient test / +3.0 D test): This test
helps in diagnosing the patients with divergence excess 2. Part time occlusion (patching the dominant eye or
due to a high AC/A ratio. In such cases the near deviation alternate patching for 4-6 hours a day may be tried in
increases by 20 PD or more on addition of a +3.0 D lens. young children. It prevents the development of suppression
and may be used to postpone surgical intervention in
4. Far distance measurement: Apart from the near and responsive patients.
distance (20 feet) measurement, the deviation must also be
measured for far distance (100 – 200 feet). 3. Overcorrecting minus lens therapy:This technique is based
on the principle that stimulating accommodative
convergence can reduce the exodeviation. (- 1 to -4 D over
the patients cycloplegic refraction is prescribed)
Fusional Control 4. Prism therapy: Base in prisms to either partially reduce
(Demand reducing) or totally neutralize the deviation may
The level of the corrective fusional control is an be prescribed with an aim of enforcing the fusional
essential baseline evaluation and is also an indicator of vergence and bifoveal fixation.
progression.
Ideal candidates for conservative therapy
1. Home control: According to Rosenbaum and Santiago 1. Young patients (4-5 years old)
the percentage of waking hours when the squint is noticed 2. Phase I or II.
by the parents is a fair measure of the level of control. A 3. Fair or better control of deviation.
deviation manifesting more than 50% of waking hours 4. Angle of deviation d”20 – 25 PD.
indicates poor control.
These patients must be monitored closely for any signs
2. Clinical control: In the clinic the fusional control can be of progression.
graded by assessing the response on cover testing
a. Good control: The patient resumes fusion rapidly
without blinking or re-fixation.
b. Fair control: Patient blinks or re-fixates to control Signs of Progression
the deviation.
1. Gradual loss of fusional control evidenced by the
c. Poor control: Patient breaks spontaneously increasing frequency of the manifest phase of squint
without any disruption.
February, 2007 14 DOS Times - Vol. 12, No. 8
2. Development of Secondary convergence insufficiency for vision therapy.
3. Increase in size of the basic deviation 2. Poorly controlled (NCS 7 or more): definite surgical
4. Development of suppression as indicated by absence intervention needed, as spontaneous recovery is unlikely.
of diplopia during manifest phase 3. Moderate control (NCS 3- 6) show better results with
5. Decrease of Stereoacuity surgical management as compared to conservative
approach.
Surgical management: Thus a surgical threshold of NCS 3 has been proposed
based on the observation that surgical intervention is
The primary aim for any squint surgery is the necessary to achieve a cure in this subgroup.
restoration of appropriate binocular function, and to
improve cosmesis. When to operate?
The decision to operate a case of IDS involves the The timing of surgical intervention is as controversial
following as the decision to operate.
1. Who will require surgical correction?
Early surgery may offer to prevent the development of
2. When to operate? sensory changes but it also carries the risk of consecutive
3. Effect of patient’s age on the surgical aim? esotropia leading subsequently to monofixation.
4. What type and how much surgery to do? Delayed surgery as advocated by Jampolsky, has the
5. How to manage any residual exotropia or consecutive advantage of accurate diagnosis and quantification of the
amount of deviation and to avoid consecutive esotropia.
esotropia?
Whom to operate? For small angle deviations (< 20 PD) and for young
children (< 4 years) it is best to defer the surgery and use
Although no clear-cut guidelines are available, various
studies have proposed different views as to when does vision therapy in the form of part time or alternate
surgery become necessary in IDS. occlusion with a close watch for signs of progression.
Large angle deviations (> 20 PD) Choice of procedure?
Documented worsening of the deviation (Signs of As per the classical teaching bilateral lateral rectus
progression) recession is the procedure of choice for pure divergence
Deviation present for more than 50%of waking hours. excess type whereas simulated divergence excess type and
basic types are best managed with unilateral recess- resect
Failure of conservative therapy. procedure.
The Newcastle Control Score (NCS) The current opinion however is in favor of symmetrical
The NCS incorporates both Score Component
objective and subjective measures
of control into a simple grading Home control
system that differentiates and
quantifies the various levels of 0 Squint/manocular eye do sure never noticed
severity in IXT 1
Squint/manocular eye do sure seen occasionally
The NCS attempts to provide a 2 (<50% of time child observed) for distance
semi-quantitative score for grading
the severity of IDS. Each level of 3 Squint/manocular eye do sure seen frequently
severity is quantified on a linear (>50% of time child observed) for distance
scale, it is a simple tool with which + Clinic control near
to measure any change over time Squint/manocular eye do sure seen for distance
and is suitable for use both clinically & near fixation
and in research
0 Manified only after cover test and resumes
The NCS categorizes the cases fusion without need for blink or refixation
of IDS into 3 groups,
1 Blink or refixate to control after CT
1. Well controlled (NCS 2): high
probability of stable course or 2 Manified spontaneously or with any form of
spontaneous recovery. Candidates fusion disruption without recovery
NCS total-Home+Clinic near+Clinic distance
DOS Times - Vol. 12, No. 8 15 February, 2007
lateral rectus recession for all types except those with with high myopic refractive error are predisposed to
convergence insufficiency, where bilateral medial rectus surgical under correction. Undiagnosed oblique muscle
resection is preferred. overaction and small vertical deviations also causes for
residual exotropia.
Goal of surgery
1. Visually immature infant: avoid consecutive esotropias Most of these will require additional surgical
procedures in the form of re recession of lateral rectus or
(can have the consequences of amblyopia and loss of additional medial rectus resection.
binocularity)
2. Older children, who develop intermittent exotropia after Over correction
age 10 years, aim for orthotropia on the first
postoperative day. Small over correction of up to 10 – 15 PD in a visually
3. Adults with longstanding IXT will tolerate under mature patient is acceptable and even desirable to some
correction, but will have symptomatic diplopia when extent. A high AC/A ratio and undiagnosed lateral
overcorrected. incomitance are the risk factors for larger angle
esodeviation. A 6 – 8 week trial of conservative measures
Surgical Success? like part time occlusion, bifocals (high AC/A ratio) or
No consensus exists for Criteria for Surgical Success. neutralizing prisms may be tried before resorting to
Anatomical Cure: Alignment within 8 – 10 PD of surgery.
orthotropia. A bimedial rectus recession is the procedure of choice
Functional Cure: Near Stereopsis between 40 – 60 sec of if surgery is needed.
Arc References
Functional Cure (Sensory alignment) is more desirable but seldom
1. Burian HM, Pathophysiology of exodeviations. Symposium on horizontal squints, St
achieved than Motor alignment. Louis, Ed Allen JH. 1950 Mosby Year Book
Under correction 2. Richard A. Saunders. Perspectives in the management of intermittent exotropia,
Patients with initially large angle deviations and those AAPOS workshop, Orlando, Florida 2001
3. Intermittent exotropia: a major review. Rahul Bhola, Eyerounds.org, Jan 2006
4. H Haggerty et al, The Newcastle Control Score: a new method of grading the severity
of intermittent distance exotropia, Br j ophthalmol 2004; 88; 233 – 235.
5. RosenbaumA,SantiagoA.IntermittentExotropia.ClinicalStrabismusManagement.
Philadelphia: WB Saunders, 1999:168.
February, 2007 16 DOS Times - Vol. 12, No. 8
MEDICALOPHTHALMOLOGY
Epiphora
Yashoda Lohia DO, Sandhya Makhija DO, DNB, MNAMS
Epiphora implies overflowing of tears due to abnormal irritation, environmental irritants like pollution.
lacrimal drainage. 3. Abnormal lid globe apposition (Fig 3)
Ectropion
Epiphora is a symptom as well as a sign rather than Entropion
an absolute diagnosis. Lagophthalmos
Centurion syndrome: medial ectropion with
Pathophysiology: Epiphora can be caused by any of the
following possible causes:- prominent nasal bridge
1. Block in lacrimal drainage pathway 4. Ocular surface disorders like chronic KCS,
Punctal block conjunctivochalasis, cicatricial ocular surface pemphigoid,
symblephron.
o Congenital absence 5. Neurogenic hypersecretory disorders like compressive
o Acquired irritation of parasympathetic lacrimal fibres, Aberrant
regeneration of facial nerve following trauma.
z Post infection e.g., Herpes, Trachoma 6. Facial palsy
z Post radiation therapy
z Post traumatic Types of epiphora
z Senile Acute- due to irritants like corneal foreign body,
z Toxicity to systemic or topical medications
Canalicular block infection, acute cold, allergic conjunctivitis, toxic fumes,
o Causes are similar to that of Punctal block. emotional stress.
o Occasionally a large hordeolum or chalazion may Chronic- results from long standing unremitting
induce punctual or canalicular stenosis. disorders.
Lacrimal sac abnormality
o Sac inflammation Symptoms
o Peri lacrimal fibrosis Watering: continuous or intermittent
o Dacryolith Blurring of vision
o Sac tumors (rare in pediatric age group) Irritation to lid especially at inner canthus
o Adnexal tumors pressing on lacrimal sac or
drainage pathway Clinical Evaluation of a patient with epiphora
Nasolacrimal duct occlusion A. History
o Membrane at the site of Hasner's valve H/O present illness
o Bony NLD block, traumatic, idiopathic, Irradiation, Does it feel wet?
Infilteration of nasolacrimal tumour. Need to wipe?
Nasal conditions Frequency?
o Severe Deviated Nasal Septum or Turbinate Unilateral/bilateral?
Hypertrophy Seasonal/ environmental allergy?
2. Excessive tears production Intermittent/ constant?
Reflex lacrimation in response to various factors like When - Reading/ working?
Trichiatic cilia, severe entropion, raised intra ocular Associated symptoms if any: glare, photophobia,
tension, allergic conjunctivitis, corneal exposure, drug
photosensitivity, or diplopia?
Department of Ophthalmology Pertinent associated sign/symptom include foreign
Sant Parmanand Hospital,
Alipur Road, Civil Line, Delhi body sensation, burning, irritation, redness, discharge,
DOS Times - Vol. 12, No. 8 17 February, 2007
bloody tears, pain, associated failure
swelling, associated URI, rhinitis B) Failure of dye to reach nose- In
or sinusitis. such cases of obstruction the site, is
usually evident
H/O past illness Fig.1: The external eye c) DCG helpful in diagnosis of
diverticules, Lacrimal fistulae, filling
Eye, orbit, facial, nasal or sinus defects due to stone or tumors.
surgery or trauma.
Lacrimal Scintillography
systemic diseases -arthritis,
thyroid disease, systemic This assesses drainage under
chemotherapy, local irradiation more physiologic conditions. It is more
therapy involving head. sensitive in assessing incomplete
blockage especially of upper lacrimal
Previous Stevens Johnson system.
syndrome
Prerequisites are patent puncta
Anti-glaucoma therapy and no lid malposition
Drugs like 5FU, idoxiuridine,
Canalicular Endoscopy
epinephrine, neostigmine, silver Microcanalicular endoscopes are
nitrate, thiopeta. Docetaxl.
available to detect site and type of
Alcohol Ether, Heparin, blockage.
Indomethacin, Ketamine,
Morphine, rifampicin.
Fig.2: Normal anatomy of the tear drainage CT SCANS: helpful in suspected
B. Examination system anatomical abnormalities (congenital
External: thorough examination of malformation), h/o previous trauma or
eyelids, ocular surface, trichiasis, tear film. Look for any any surgery done, in enlarged sac (h/o bloody tears),
skin disease like psoraiasis, atopic dermatitis, allergic scanning of maxillary and paranasal sinuses and planning
blepheritis. Lid lag or lagopthalmos, any displacement of of surgery.
globe, sac palpation.
Slit lamp biomicroscopy: for subtle abnormalities of eyelids, Summary of diagnostic procedures:
position of punctas, size and patency, discharge, size of Careful history
caruncle, eyelid laxity, blinking mechanism, marginal tear External examination
strip, Tearfilm debris, papillae or follicles, pinguecula,
pterygium, conjunctival chelosis. Ocular cicatricial Slit lamp biomicroscopy
pemphigoid. Syringing and probing
Imaging in complex cases
C. Clinical diagnostic tests
Fluoroscein dye dissapearance Differential diagnoses of wet eye symptoms
test
Symptoms Possible Causes
Syringing and probing: done to 1. Sensation Of Wetness
determine the patency and the 2. Looking through water 1. Mucus in tearfilm, epiphora
site of obstruction.
3. Intermittent tearing 2. Epiphora, mucus in tear film, ocular
Dye test: It is done in suspected media opacity, maculopathy, optic
patients of partial obstruction or neuropathy
functional epiphora.
3. Ocular surface disorder, Lid abnormalty,
Taste test Facial Nerve Palsy, Laxity of eyelids
(Fig. 4), ectropion, dacryocystitis (Fig. 5)
Imaging 4. Itching 4. Allergy
5. Burning 5. Dry Eye, Exposure Keratopathy
Contrast Dacryocystography 6. Tears while reading
6. Refractive error, ectropion, Lower eyelid
A) Normal DCG in presence of 7. Bloody Tears laxity
epiphora- may imply partial
obstruction or lacrimal pump 7. Mass, Acute Ethmoidal/Frontal sinusitis
February, 2007 18 DOS Times - Vol. 12, No. 8
Aims of management: Fig.3 Fig.4 Fig.5
Alleviate the symptoms
Correct the underlying
disorders
Epiphora In Children
Failure of the canalization of Fig.3: Abnormal lid apposition: Lower lid ectropion, Fig.4: Lower lid laxity causing excessive
the lower part of the nasolacrimal tearing, Fig.5: Chronic dacryocystitis causing epiphora
duct results in congenital
dacryocystitis. dacryocystitis is still controversial. A brief outline of the
The clinical manifestations of congenitally closed NLD management strategy is given in table 2.
are:
a) Congenital lacrimal amniocele: Conservative management
b) Congenital dacryocystitis: Can present as acute mucocele a) Lacrimal massage (Fig 6): Lacrimal massage and
or pyocele in the neonatal period. installation of antibiotic drops is the most widely accepted
c) Persistent tearing and matting of eyelashes without initial management strategy for congenital NLD block.
acute dacryocystitis. Usually children have chronic
About 90% of the congenital blocks open spontaneously or
epiphora and chronic mucopurulent discharge. A with proper massage. Lacrimal massage is done with the
pressure regurgitation test may be positive.
idea of increasing the hydrostatic pressure inside the
lacrimal sac to open the distal membranous obstruction.
Management of Congenital Dacryocystitis Hence proper positioning of the finger is very important
The management protocol for congenital during the massage. Massage is done by putting the index
finger over the common canaliculus to
Table 1:Differentiating signs of common causes of epiphora occlude this opening to prevent the
Category Condition Distinguishing characteristics reflux of the secretions through this
opening and then stroking firmly
Outflow obstruction Canalicular Painless; minimal discharge downward to increase the hydrostatic
Eyelid abnormalities obstruction pressure inside the sac. Mother must
Nasolacrimal Painless; moderate discharge,
duct obstruction lid erythema be taught properly to fixate the head
Partial duct Painless; intermittent tearing of the child in between her legs and to
obstruction
Punctal stenosis Painless; visibly small puncta put the pressure over the lacrimal sac
and occluding the common canaliculi
Blepharitis Scaly lid margins, lid edema,
chalazia at the same time. This procedure must
Distichiasis Extra row of eyelashes touching be done 3-4 times per day and 10-12
eye surface
strokes are applied during each sitting.
Topical antibiotic drop is installed
after the procedure.
Entropion Upper or lower eyelid turning Advantages of lacrimal massage
Lagophthalmos inward Empties the lacrimal sac and
Eye surface irritation Conjunctivitis Poor eyelid closure with corneal hence prevents stasis of secretions and
Corneal abrasion exposure bacterial growth.
Red conjunctiva, gritty Helps in opening up the
sensation, discharge membranous blockage at the lower
Painful; photophobia, corneal and of NLD.
staining
Foreign body Painful; photophobia, eyelid Surgical management
Keratitis closure
Painful; photophobia, corneal (a) Syringing and Probing: The time for
Infantile glaucoma Congenital lesions surgical intervention in case of
glaucoma congenital NLD obstruction is still a
Photophobia, enlarged and matter of controversy. Early probing
hazy cornea (before 6 months of age is said to
DOS Times - Vol. 12, No. 8 19 February, 2007
reduce the chances of
secondary infection and
the duration of
symptoms. However
majority of the
congenital NLD block Fig.7: Aquired dacryo- Fig.8: Lester Jones tube
opens spontaneously by cystitis
6 months to 1 year,
Fig.6: Lacrimal massage hence waiting for this general condition does'nt permit DCR surgery. Balloon
catheter is passed over a guide wire and inflated at
period might obviate different levels inside the NLD to break the obstruction.
the need for surgical intervention. We prefer to give the e) Pediatric Dacryocystorhinostomy
first trial of probing at 9 months of age if the conservative The earliest time at which a DCR is usually done is 3
management fails.
Indications of probing years. The chances of failure of the DCR procedure are more
Failure of Criglers massage and the child in the pediatric age group than adults because of more
is > 9 months old. Table 2: Management protocol for Congenital Dacryocystitis.
Congenital lacrimal amniontocele (even
if the child in < 9 months of age). Congenital NLD block
If the symptom persist or recurs after the
first probing the procedure can be repeated • Criglers Massage
Topical antibiotic till 9 months
twice at an interval of 4- 6 weeks. If repeated
probing fails, a nasal examination should be
done to rule out any hypertrophied inferior
turbinate, nasal polyp or a narrow inferior Resolves No resolution
turbinate. Inferior turbinate infracture is
done in cases of narrow meatus with
impaction of the inferior turbinate against Observation Syringing and Probing
the lateral wall of the nose.
b) Inferior turbinotomy
Punctal dilation and nasolacrimal Resolves No resolution
irrigation is always contra-indicated in the Resolves Repeated
acute stages due to risk of inducing preseptal
cellulitis.
c) Silicon Tube placement
When the above mentioned procedures No resolution
fail, silicone tube intubation is done. Tube
placement is done by putting the stylus in a Nasal examinationto R/O;
similar way as passing a lacrimal probe and • Turbinatehypertrophy
retrieving the tube from the nose. Inferior
turbinate infracture may need to be done in Narrow meatus
some cases. Both the ends of the tube are
knotted on themselves, cut and allowed to Polyp
retract into the nose. The tube is left in situ
for 3 months and removed subsequently. Silicon intubation Inferior turbinateinfracture
d) Balloon catheter dilatation:(BALLOON No resolution
DACRYOPLASTY) DCR after 3 years of age
This can be done as an alternative to
silicon tube intubation specially in children
above 13 months of age. Also useful in adults
with incomplete nasolacrimal duct
obstruction specially in patients whose
February, 2007 20 DOS Times - Vol. 12, No. 8
Fig.9: Lester Jones tube in situ reactive granulation 5. Lacrimal mucocele
tissue formation at the 6. As a part of conjunctival or canalicular DCR
late failure due to scarring. osteotomy site in the
former group. Hence in Contra-indications of DCR
children a large bony 1. Lacrimal sac tumors
opening is to be made 2. Acute Dacryocystitis
and both anterior and 3. Very young child (<3 yrs)
posterior flaps should 4. Cicatrized and shrunken sac
preferably sutured. 5. Gross nasal disease like atrophic rhinitis, rhinitis
Anti-metabolites can
be applied in selected ozaena, para nasal suppuration, severe DNS or
cases and prevents the turbinate hypertrophy
6. Adnexal tumors growing in to the lacrimal sac
Acquired Dacryocystitis 7. Syphilis, tuberculosis or other diseases of the lacrimal
sac.
Dacryocystitis in adults is seen in association with
nasolacrimal duct obstruction. Usually adults more than Role of canalicular stents
40 yrs of age are affected with a female preponderance Indications include
(Male: female ratio is 4:1). Stasis of the secretions inside the Re DCR
sac predisposes to infection inside the sac. (Fig 7) Inability to suture the lacrimal and nasal flaps (loss of
Types flap or thin nasal mucosa)
Inadequate bony opening.
1. Acute dacryocystitis: It can present either as an
Acute suppurative dacryocystitis The bicanalicular tube should stay for at least 6 weeks
Acute pericystitis: Here the infection reaches the for the tract to get fully epithelialized.
perilacrimal tissue directly from neighbouring Complications of DCR surgery
structures without prior involvement of the sac itself. Intra operative
Acute gangrenous dacryocystitis
z Loss of nasal or lacrimal flaps
Management of acute dacryocystitis z Uncontrolled Bleeding
Management is conservative with systemic and topical
¾ Angular Vein
antibiotic and anti-inflammatory medications. Syringing ¾ Periosteum
and probing are contraindicated in acute stage. Lacrimal ¾ Nasal mucosa
abscess, if forms, needs to be drained. A lacrimal fistula Post operative
can form following a spontaneous rupture of lacrimal z Hemorrhage
abscess or after surgical drainage. ¾ Early (<24 hrs)
2. Chronic dacryocystitis ¾ Reactionary (delayed, 4-7 days, clot retraction)
Chronic catarrhal z Orbital emphysema
Mucocele z CSF leak
Encysted mucocele z Infection
Chronic suppurative z Orbital hemorrhage
z Ectropion
Management of chronic dacryocystitis z Persistent epiphora
Management is primarily surgical and z Epicanthal fold
z Scar
dacryocystorhinostomy (DCR) is the procedure of choice.
Modifications of DCR: Special Situations
Indications of dacryocystorhinostomy (DCR) Modifications of the primary external DCR procedure
1. Chronic Dacryocystitis
need to be done in certain situations. This modification
2. Incomplete NLD block with persistent epiphora
3. Atonic sac
4. Dacryolith
DOS Times - Vol. 12, No. 8 21 February, 2007
may be in relation to the route of the surgery. The level of conscious patient
the obstruction in the drainage system and the presence of
associated pathology also change the surgical plan. To remov e adhesions or closure of the communication
made by a previous DCR
Level of Obstruction: The conventional DCR procedure
needs to be modified depending on the level of the blockade In presence of nasal pathologies like severe DNS,
at the drainage system. The primary procedure is suited turbinate hypertrophy or nasal polyp.
for cases with obstruction in the NLD. However when the
block is at the level of common or individual canaliculi or It has a poor surgical success rate (68-85%) than
punctum, a canalicular or conjunctival DCR has to be done conventional DCR (90-95%) because of a small osteotomy
to restore the normal tear outflow pathway. formation (7-8 mm). Also the lacrimal and nasal mucosal
flaps are not sutured, thus increasing the chances of failure.
1) Canaliculo DCR Modifications depending on coexistent pathology
Indications
1) Dacryocystitis with fistulae: Lacrimal fistulae can form
1) Common canalicular obstruction following spontaneous rupture of a lacrimal abscess or
2) Closure of distal ends of individual canaliculi (at least after surgical drainage. Presence of fistulae requires a
fistulectomy with excision of the fistulae tract.
8 mm of canaliculus from the punctum is patent) in
cases of bicanalicular blocks 2) Encysted mucocele: An atonic sac with an NLD block
3) Failed DCR surgery with a small residual sac causes retention of the inflammatory exudates inside the
sac and a fluctuant swelling forms below the medial
2) Conjunctivo DCR / Lacrimal Bypass Surgery canthal tendon. With time, a common canalicular block
Indications can also occur, giving rise to the formation of an encysted
1) Less than 8mm of residual patent proximal canaliculi mucocele. In these cases, the sac might get cut accidentally
2) Punctal agenesis while giving the skin incision or separating the sac.
3) Severe canalicular trauma
4) Unsuccessful canalicular DCR 3) Traumatic dacryocystitis: Traumatic dacryocystitis is a
5) Lid globe malposition specific entity and the etiology of the obstruction could be
6) Canalicular stenosis impaction by bony fragments or direct laceration. Every
7) Tumors of the inner canthus case needs to be investigated on an individual basis for the
Complications etiology and managed accordingly.
Tube extrusion
Canthal granuloma References
Conjunctival erosion
Tubal blockage (avoided by reverse Valsalva 1. Paul TO, Shepherd R. Congenital Nasolacrimal Duct Obstruction. J Pediatr
Ophthalmol Strabismus 1995 Jul-Aug; 32(4): 270-1.
technique)
2. MainiR,MacEwen CJ YoungJD.TheNaturalHistoryofEpiphorainChildhood.Eye
3) Dacryocystectomy (DCT) 1998; 12: 669-71.
Indications
Severely shrunken sac 3. Mannor GE, Rose GE frimpon-Ansah, Ezra E, Factors Affecting the Success of
Sac tumor Nasolacrimal Duct Probing for Congental Nasolacrimal Duct Obstruction. AmJ
Gross nasal pathology Ophthalmol 1999 May; 127 (5): 616-7.
Failed DCR
Elderly patients with chronic dacryocystitis without 4. Aggarwal RK, Misson GP, Donaldson L Willshaw HE. The Role of Nasolacrimil
Intubation in the Management of Childhood Epiphora. Eye 1993, 7: 760-2.
epiphora
5. Beigi B, Westlake W, Chang B, Maarsh C, Jacod J. Dacmcystorhinostomy in shouth
Modifications in the route of surgery West England. Eye 1998: 12: 358-62.
A. Endoscopic Nasal DCR
Indications 6. Guzek JP, ChingAS, Joang TA, Dure-Smith P, Llaurado JG, Yau DC, Stephenson CB,
As a primary procedure especially in a cosmetically Stcphemon CM, Elam DA. Clinical and Radiologic Lacrimal testing in Patients with
Epiphora. Ophthalmology 1997 Nov; 104 (11); 1875-81.
7. Irfan S, Cassels-Brown A, Nelson M. comparison Between Nasolacrimal Syringing/
Probing/Macrodacryocystography and Surgical Findings in the Management of
Epiphora. Eye 1998; 12; 197-202.
8. WearneMJ,PittsJ,FramkJ,RoseGE.ComparisonofdacryocystographyandLacrimal
Scifigraphy in the diagnosis of Functional Nasolacrimal Duct Obstruction. Br. J
Ophthalmol 1999l; 83 : 1032 -1035.
9. Shun-Shim GA. Endoscopic Dacryocystorhimostomy :APersonal Technique. Eye
1998; 12:467-70.
10. Perry JD, Maus M, Nowimki TS, Penne RB. Balloon Catheter Dilation for treatment
of Adults with Partial Nasolacrimal Duct Obstruction: A preliminary Report. AMJ
Opthalmol 1998 Dec; 126 (6) : 811-6.
11. Psilas K Eftaxias V Kastanioudakis J, Kalogeropoulos C. Silicone Intubation as an
alternative to Dacryocystorhinostomy for Nasolacrimal Drainage Obstruction in
Aduts. EurJ Opthalmol 1993 April-June; 3(2): 71-6.
12. MunkPL,LinDTC,MorrisDC.Epiphora:treatment;bymeansofDacryocystoplasty
with balloon dilation of the ansolacrimal draingage apparatus. Radiology 1990; 177:
687-690.
February, 2007 22 DOS Times - Vol. 12, No. 8
MEDICALOPHTHALMOLOGY
Corticosteroids in Ophthalmology- An Overview
Sanjay Ahuja1 MD, DNB, Aditi Gupta1 MS, DNB, Aparna Ahuja2 MD
CSd inhibit Phospholipase-A2 thereby inhibiting both with diluted side effects.
Lipoxygenase & Cycloxygenase pathways while most
NSAIDs (except Diclofenac) block only the cycloxygenase Cyclodextrin preparations of Dexamethasone are (e.g. in
pathway. Gate-Dx & Apdrops-Dx) now commercially available.
Cyclodextrin molecule significantly improves the Dexa
CSd also inhibit histamine synthesis & complement penetration through the cornea (drugs need biphasic
system. solubility to pass easily through the cornea as is provided
by complexing with Cyclodextrin).
Anti-inflammatory potency of CSd is different on
systemic use than from their ocular application e.g. while Out of all the commercially available CSd drops,
dexa & betamethasone are more potent inflammatory prednisolone acetate (1% suspension) is the most efficacious
steroids than prednisolone when given systemically, anti-inflammatory drug. Probably Cyclodextrin
prednisolone (pred ) acetate is far more potent than preparations of Dexamethasone are also as efficacious.
dexamethasone sodium phosphate when given topically
because of better corneal penetration. Side effects of topical steroids-
Topical CSd- Glaucoma (OAG type), secondary infections (esp. viral
e.g. herpetic activation & fungal), delayed wound healing,
Commercially available preparations- dry eyes, corneal & scleral melting enhancement (by
Prednisolone acetate (1% usually, also 0.12% e.g. increasing collagenase activity), posterior subcapsular
Predace-LD) cataract, ptosis & mydriasis (last two are actually vehicle
Dexamethasone/Betamethasone sodium phosphate related).
(usually 0.1%, also 0.05% & 0.01%)
Topical medroxyprogesterone acetate (1%) is a milder
Flurometholone acetate (0.1% & 0.25%) CSd that suppresses inflammatory & immunological
Loteprednol etabonate (0.5%) damage without increasing the corneal melting as it
inhibits the collagenase enzyme.
All acetate preparations (e.g. Prednisolone, Steroid induced glaucoma (is of OAG type with reduced
flurometholone, and hydrocortisone) are in suspension
outflow facility) is commoner on topical use but it can also
form; hence these must be shaken well before use. occur on systemic (oral or IV) use, skin, nasal & other
Phosphate salts of Dexa/Betamethasone are less surface applications. IOP returns gradually to normal on
effective than acetate or
alcohol salts. Phosphate salts
are the ones primarily used in Me cha nism of clinica l effe cts
most of their eyedrop Phospholipids of d estroyed cell membran es
preparations.
Dexa/Betamethasone is P hospholipase-A2 .(inhibited by CSd )
normally used in 0.1%
concentration; however Lipoxyg enase -path way Arachid onic acid Cycloxygenas e path way
commercial preparations are
now available in diluted Leu kotri e nes Prostag landins & Endo peroxides.
forms e.g. 0.05% in Lowdex,
0.01% in Decolite & Solodex-J. (main media tors of inflam mation)
These are supposed to have
retained the anti-
inflammatory potency but
1. MM Eyetech, Lajpat Nagar, New Delhi withdrawing steroids (rarely months, if IOP rise was
2. Ahuja Child & Eye Centre severe). Predisposed patients include those with positive
family history (genetic), diabetics, high myopes, etc.
36, Parmanand Colony, Delhi-110009 Presumptive cause is mucopolysaccharide deposition in
DOS Times - Vol. 12, No. 8 23 February, 2007
trabecular meshwork. Commonly used Systemic & Periocular commercial CSd preparations
CSd drop preparations that are 1. Hydrocortisone Na Succinate (soluble salt) e.g. Efcorlin
less likely to cause secondary inj. (100mg HC vial in powder form).
glaucoma include: Acetate salt (insoluble) e.g. Wycort (5ml
vial of 25mg/ml)
i) Medrysone (1%) - is no more
available now, is less efficacious 2. Dexamethasone(Decadan Tablet of 0.5 mg.
& has poor corneal penetration. & Dexona) Injection of 2 ml ( 4mg/ml).
ii) Loteprednol etabonate (e.g. Paediatric oral drops 0.5 mg/ml e.g.
Lotepred, Loteflam) is rapidly Dexona
deactivated by cellular esterase
enzyme inside the anterior 3. Betamethasone (Betacortril, Tablet of 0.5 mg & 1mg.
chamber & on the surface of the Betnesol, Celestone) Inj. of 1ml/2ml/3ml- each containing
eye.
4mg/ml.
iii) Flurometholone (0.1% & 0.25%) Paediatric drops 0.5mg/ml
Anti-inflammatory efficacy of 4. Prednisolone (Deltacortril, Tablet of 5/10/20 mg.
Wysolone)
steroids is probably related to their
ocular hypertensive effect.
5. Methylprednisolone Na succinate salt (soluble) -8ml(500mg)/
Periocular injections 16ml(1000 mg) of 62.5 mg/ml e.g.
Solumedrol
Only water soluble CSd Acetate salt (suspension)-1ml/2ml inj. of
preparations (i.e. phosphate salts) 40 mg/ml e.g. Depomedrol.
should be given by subconjunctival
route while insoluble acetate salts are 6. Triamcinolone(Kenacort & Tablet of 1 mg/4 mg.
given by subtenon’s route (if given Tricort) 1 ml inj. of 10mg/ml or 40 mg/ml
subconjunctivally unsightly deposits
can form which might also cause
discomfort). Oral steroids given as single dose early in the morning
Before giving subtenon steroid depot, ensure that the (never with empty stomach) is considered more
patient is not a steroid responder (patient should have been on physiological (less adrenocortical suppression).
topical steroids for about 4 weeks as it may take 2-4 weeks Alternate day therapy is still more physiological but
for steroid induced glaucoma to appear after topical inflammations may not respond well to such a therapy,
application). hence shifting to alternate day regime may be more suited
Effects of subtenon’s depot steroid (Depomedrol/methyl- while tapering steroids. For this, double the dose on
prednisolone acetate, 20 mg/0.5ml or Wycort/ alternate days & then taper. On the ‘off-day’, patient will
Hydrocortisone acetate, 12.5mg/0.5ml) lasts for 1-2 weeks. feel fatigue, joint pain, muscle stiffness or tenderness, etc.
It is especially useful for unilateral intermediate or (all being the symptoms of relative adrenal insufficiency).
posterior uveitis where steroids get delivered selectively Systemic CSd will be more preferable for ocular
in high concentration avoiding any systemic side effects. diseases with possible autoimmune etiology e.g. thyroid
Route of periocularly given steroid absorption is trans- eye disease, pseudotumor, sarcoidosis, etc.
scleral unlike subconjunctival antibiotics that are absorbed Oral CSd are never given on an empty stomach. Always
through the cornea after flowing back through the combine them with antacids or proton pump inhibitors
punctured needle site. Hence steroids should be placed e.g. Omeprazol/Isomeprazole (Raciper-20).
closer to the site of inflammation. Depot CSd are always
avoided in scleritis (scleral melting is possible). Always taper them slowly depending upon the
duration of the treatment (no tapering required if given for
Depot steroids’ induced glaucoma may need excision <1 week) to overcome the adrenocortical suppression.
of depot surgically
Any patient taking >7.5mg/day of pred (or equivalent)
for > 3 months or 40 mg/day for >1week is presumed to
Oral & Intravenous steroids have significant adrenocortical suppression. In these
Because of having shorter half life, systemic patients, even for minor stresses like eye surgery under
prednisolone is more physiological than Dexa/ local or topical anesthesia, 25mg of hydrocortisone should
Betamethasone. be given IV just before the surgery.
February, 2007 24 DOS Times - Vol. 12, No. 8
Pulse steroid therapy- High dose pred (1gm bolus as slow Tricort & Kenacort contain vehicle in the form of benzyl
IV infusion or 250mg 6 hourly) is used in certain severe alcohol (could be toxic to retina) which many people don’t
ocular inflammatory disorders e.g. optic neuritis, severe remove before injection (found in supernatant after
corneal graft rejection, sympathetic ophthalmia, VKH suspension is allowed to settle). Preservative free
syndrome, etc. See under the heading below section on preparation is also now commercially available.
optic neuritis & optic nerve injury (mega dose steroid
therapy). Intra-vitreal it injection is given in mid or posterior
vitreous cavity under direct visualization under the sterile
Important side effects of systemic CSd- conditions in OT in the inferotemporal quadrant to avoid
S- pSychosis, headaches, pSeudotumour cerebri. drug deposition in the visual axis.
T- Thrombosis (venous)
E- Endocrinal- suppressed hypothalamic-pituitary- Effect is usually transient and repeat injections are required
after 3 months or so.
adrenal axis, retarded growth, cushingoid state.
R- Retention of fluid & sodium but loss of potassium & Especially used for chronic diffuse diabetic macular
edema (DME). CSd being antiprostaglandin & antiVEGF
systemic alkalosis. (hence angiostatic), they reduce the vascular permeability
O- Osteoporosis & myopathies. and macular edema.
I- Immunosuppression with secondary infections esp.
Multicentric US study is on to test the efficacy of IVTA
TB & fungal, in DME.
D- Diabetes & hypertension, Duodenal & gastric (peptic)
IVTA is also useful to stain ERM & ILM during VR
ulcers. surgery.
Daily dose of 10 mg or more Prednisolone therapy
commonly causes Cushingoid features on long term Macular edema of other causes like uveitis, parafoveal
therapy. telangiectasias, radiation induced, vascular occlusions, etc.
may also respond favourably to IVTA.
Systemic CSd in pregnancy-
CSd can have teratogenic effects (congenital Specific VEGF inhibitors (e.g. Avastin) given
intravitreally are now being preferred more as compared
malformations, cataract, etc) & adrenocortical suppression to triamcinolone especially in disorders with macular
in newborn. CSd are also excreted in breast milk in CNVM (e.g. ARMD) as they probably ‘cure’ the root cause
lactating mothers & can cause adrenocortical suppression unlike just temporary symptomatic lessening of edema
& growth retardation in infants. with triamcinolone.
Steroid induced cataract: Sustained release steroid implants (implanted surgically
is governed by total cumulative dose of steroid. inside the eyeball) provide slow, steady & sustained release.
both prolonged topical & systemic CSd usage can cause Main disadvantages are high incidence of increased IOP &
cataract.
cataract (primarily PSC & is generally irreversible)
Cataract induced by post systemic CSd use is bilateral. i) Envision TD implant from B&L (Flucinolone acetonide)
Dose of >15 mg/day of prednisolone (or equivalent) for chronic uveitis- synthetic CSd in a non-
biodegradable pellet which releases CSd at a constant
given for a year induces cataract in > ¾ th of the rate for almost 3 years.
patients although no definite dose linking may always
be possible. ii) Posurdex from Allergan (Dexamethasone implant) has
Diabetics & younger patients are more prone. a biodegradable coating.
Intravitreal steroids Role of Corticosteroids in various diseases & their dosing
Depot steroid (Triamcinolone ‘TC’ acetonide/ Tricort or schedules-
Kenacort 40 mg/ml inj) is used. TC is non-toxic to retina & 1. Scleritis- Tried as first or second line drug to NSAIDs.
has long retention time hence is the preferred intra-vitreal Topical steroids are not effective unlike in episcleritis.
it steroid. Periocular steroids are contraindicated (chances of scleral
thinning & perforation). CSd (oral Pred 1-1.5 mg/kg/D) is
Dose=0.1 ml (4 mg). Even 2 mg is said to be equally given for 2-3 weeks followed by slow tapering. Systemic
effective. NSAIDs alone might suffice or short course of systemic
CSd is combined with it. If immunosuppressants are
required, simultaneous systemic CSd given for about 4-6
weeks during chemotherapy induction are useful.
2. Chalazion- Intralesional steroid injn. (0.2 to 0.5 ml
DOS Times - Vol. 12, No. 8 25 February, 2007
of Triamcinolone acetonide injection of 40 mg/ml depending endothelial rejection. Topical CSd 4x/day for epithelial
upon the size of the chalazion) is sometimes tried if patient rejection (relatively benign). Systemic CSd, if topical CSd
refuses surgery or if it is close to the lacrimal canaliculi. fail or recurrence occurs. For severe rejection (generalised
Permanent eyelid skin depigmentation is possible. corneal edema), IV methyl Pred (pulse steroid therapy) is
given along with intensive topical CSd (1 hourly). It is an
3. Periorbital Dermatitis (Atopic, Contact allergic, Irritant, ocular emergency
Seborrheic). Most patients benefit from short course of topical
CSd ointment application for 1-2 weeks. Short course of 11. Anterior uveitis- In acute non-granulomatous uveitis,
systemic CSd (pred 1mg/kg/D for 4-5 days followed by give topical pred acetate drops every 1-6 hourly depending
tapering over next 10 days) may be given for severe lid on the severity. Periocular steroids are used for non-
swelling in contact dermatitis. compliant patients. Simultaneous cycloplegic therapy is
must.
4. Allergic conjunctivitis (Hay fever, AKC, VKC, GPC,
Phlyctenular)- CSd bring dramatic improvement with 12. Intermediate uveitis-
potential side effects. Topical CSd are used only as 2nd or 3rd
line drugs. Use diluted CSd (e.g. 0.01% Dexa or 0.12%Pred) i) Topical CSd are not much effective. Might be given along
or milder CSd (e.g. Flurometholone, Medrysone, with periocular CSd.
Loteprednol) as pulse therapy (4-8x/day for 1 week
followed by fast tapering). Tear substitutes, Antihistamine- ii) Periocular CSd (posterior subtenon’s injection of
vasoconstrictor combination, Mast cell stabilizers are the combination of steroid depot e.g. Triamcinolone
first line drugs generally. Olopatadine has both acetonide 0.5ml of 40mg/ml & short acting CSd e.g.
antihistaminic & mast cell stabilizing properties. 0.5ml of dexamethasone 4mg/ml. Repeat injections may
be given at 2-4 weeks interval.
5. Chronic Adenoviral Keratoconjunctivitis- Topical CSd
only temporarily resolve the subepithelial infiltrates iii) Systemic CSd (pred 1 mg/kg/D) is required in bilateral
without affecting the clinical course. There is no correlation cases or those not responding to periocular injections
between the use of CSd in acute phase and its going into (after 2-3 injections have been tried) or those with
chronicity. Spontaneous resolution usually occurs in weeks severe inflammation.
to months.
Generally no treatment is required if visual acuity is
6. Herpetic (H. simplex) stromal keratitis- CSd >/= 6/12. Rule out steroid responders & infective etiology
contraindicated in any form of active epithelial keratitis (e.g. Toxoplasmosis) before any periocular injection.
while topical diluted CSd (1:10 dexamethasone) bd/tds is
useful for stromal disease (immunological basically) & is 13. Posterior uveitis- Non-specific posterior uveitis needs
given along with prophylactic antiviral treatment. CSd pred (1-2 mg/kg/D). Very severe cases may need IV Methyl-
increase the viral replication. Mild topical CSd may be pred (1gm/D). Depot CSd implants (of Flucinolone acetonide
given for severe inflammation. & Dexa) are relatively new surgical options (q.v.). In active
ocular Toxoplasmosis, avoid CSd without concomitant
7. Corneal chemical injury- Give topical steroids (1% specific anti-toxo treatment.
pred acetate qid to 2 hourly depending upon the severity)
for the first week only followed by shifting to topical VKH cases need 1-2mg/kg/D of pred initially & then
NSAIDs. CSd don’t affect epithelial wound healing. Risk of maintenance dose for 6-12 months. In Sarcoidosis, start
corneal melting/ulceration is very minimal in the first week with 1-2mg/kg/D of pred. Taper slowly by 5-10mg/D every
of chemical injury. After this period, stromal collagen repair 2 weeks & then maintain on 10-15 mg/D for 6-8 months.
is inhibited by CSd, hence avoid them after a week.
14. Postoperative endophthalmitis-
8. Herpes Zoster Keratitis- Topical CSd are used for
stromal keratitis & uveitis. Sometimes also used for i) In early endoph (starts within days & is unlikely to be
epithelial keratitis (use cautiously as neurotrophic keratitis fungal); along with antibiotics, give topical CSd (pred
might be associated). Unlike in H. simplex epithelial acetate 1-2 hrly) or I-Vit Dexa (0.4 mg) with antibiotic.
keratitis, topical CSd don’t increase viral replication in Some give oral CSd (predni 1-2 mg/kg/D) after patient
Zoster epithelial keratitis. Zoster keratitis are generally starts responding in 24-48 hours. Their role is
the pseudodendrites (elevated mucous plaques) that are controversial.
fluorescein stain negative.
ii) Late endoph (starting after a week) - Avoid all CSd
9. Corneal edema- Topical CSd are useful only in until fungus infection is ruled out & patient is definitely
inflammatory edema e.g. that is caused in uveitis, bacterial responding to antibiotics. Similarly avoid CSd in post-
keratitis, graft rejection & NOT the one due to dystrophy traumatic endoph till fungal infection is ruled out.
(e.g. Fuch’s).
15. Sympathetic ophthalmia- Oral Pred (1-2 mg/kg/D) till
10. Corneal graft rejection- Topical CSd every hourly for inflammation subsides followed by very slow tapering
(may be for months). CSd are of no prophylactic value in
its prevention.
16. Cystoid macular edema (CME)- Most cases of
February, 2007 26 DOS Times - Vol. 12, No. 8
postoperative CME (Irvine-Gass syndrome) resolve Only observe, in cases of recurrent ON or known case
spontaneously. No definite benefit has been found with of multiple sclerosis.
the use of topical or systemic CSd in an established case of
CME. CME of DR, vascular occlusions, uveitis, etc. are helped 22. Optic nerve injury- Immediately institute ‘Mega’
by IVit Triamcinolone (2-4 mg) as previously described. intravenous methyl-pred doses like that for spinal cord
Effect comes in 2-3weeks & lasts for 2-3 months. Steroid injuries. Loading dose of 30mg/kg by slow IV infusion
depot (q.v.) implants are also under trial. followed by maintenance dose of 5.4mg/kg every hour for
48 hours. If condition is improving, shift to oral pred,
17. As Post-operative treatment- In most intraocular & otherwise go ahead with surgical decompression.
ocular surface surgeries, topical CSd are usually given
according to the severity of inflammation for few days to Monitor the visual acuity & relative afferent pupillary
weeks. defect (RAPD) closely.
18. Acute retinal necrosis (ARN)- Oral Pred (0.5-1.5mg/kg/ 23. Arteritic Ischemic optic neuropath- Once Giant cell
D) after 1-2 days of intravenous Acyclovir initiation. arteritis (GCA) is suspected in a case of AION, immediately
Continue treatment for 6-8 weeks followed by gradual start pulse steroid therapy (IV methyl pred 250mg 6 hourly
tapering. X3days). This is followed by oral pred (1-2mg/kg/D) for 2-
4 weeks if temporal artery biopsy is positive, thereafter
19. Thyroid eye disease- Systemic CSd (Predni 1-2mg/kg/ taper slowly & maintain on CSd for 6 months to a year
D for significant proptosis causing exposure keratopathy, (monitor ESR). Blindness from GCA is usually permanent
significant diplopia or vision loss because of optic & CSd basically help to prevent it in the other eye as the
neuropathy. Many steroid courses may be required to cure contralateral eye can get involved within 24 hours.
frequent recurrences. IV methyl-Pred may be required for
severe exophthalmos. 24. Infantile hemangioma (strawberry angioma)- Benign &
largely resolves on its own (but never completely)
20. Orbital pseudotumour- Early & aggressive systemic
CSd therapy is the mainstay of treatment. Oral pred (1-2 Intralesional steroid injection is no more preferred
mg/kg/D) for 2-3 weeks followed by slow tapering (5-10mg/ (1ml/40 mg of Triamcinolone +1ml/6mg of Betamethasone
week). For recurrent & non-responding cases, retrobulbar NaPO4 given as mixture as deep injection avoiding an
or intralesional CSd injection may be tried. NSAIDs may inadvertent intravascular injection) because of possible
be added especially to relieve pain. Low dose orbital localised skin changes, systemic side effects can occur in a
irradiation & immunosuppressives are the alternatives. child & inadvertent intravascular injection can cause
ophthalmic artery obstruction. For actively growing
21. Optic neuritis- If patient seen early, give ‘pulse steroid lesions, oral pred (1.5-2mg/Kg/D) for 1 week helps. Repeat
therapy’- IV methyl pred (by slow IV infusion over 30 min treatments are often required to treat recurrences.
daily X 3 days or 250mgIV 6hourly X 3days followed by
oral prednisolone 1 mg/kg/D X11days with tapering over Suggested readings
a week. Probably equally effective alternative is to give
Decadron 100mg IV in place of methyl-pred. Monitor BP & 1. Haynes R.C., Murad F: Adrenocorticotropic hormone: Adrenocortical steroids and
pulse every 15 minutes during infusion. Get serum their synthetic analogs. Inhibitors of adrenocortical steroid biosynthesis. Goodman
electrolytes also. Oral CSd not recommended, recurrences & Gilman’s The pharmacological basis of therapeutics: New, MacMillan.
become commoner (ONTT study). MRI scan (cranium) to
rule out multiple sclerosis must be done. 2. LeibowitzHM,RyanWJJr,Kupperman:Acomparativeanti-inflammatoryefficacy
of typical corticosteroids with glaucoma inducing potential. Arch. Ophthalmol. 1992;
It is actually a self limiting disease. IV CSd offers- 110:118-120.
Reduced recurrence rate 3. Beck RW, Cleary PA: The optic neuritis study group. Optic Neuritis Treatment Trial.
Shortened visual recovery time. Arch. Ophthalmol. 1993; 111: 773-775.
But no long term visual benefit 4. Floman N, Zor U: Mechanism of steroid action in ocular inflammation. Invest
Reduces risk of developing multiple sclerosis. Ophthalmol. Vis. Sci. 16:69, 1997.
5. Freidlaender MH: Corticosteroid therapy of ocular inflammation. Int. Ophthalmol.
Clinics. 23:175, 1983.
6. Cantrill HL, Palmberg PF, Zink HA, et al: Comparison of in vitro potency of
corticosteroids with ability to raise intraocular pressure. Am. J. Ophthalmol. 79:1012,
1975.
7. Mark B. Abelson & S. Butnis: Corticosteroids in ophthalmic practice. Principles &
Practice of Ophthalmology. Albert & Jackobie, Vol.1 pp. 258-265.
8. Fechner & Teichmann: Ocular therapeutics- Pharmacology & clinical application,
Slack Incorporated. Corticosteroids. Pp.97-105.
DOS Times - Vol. 12, No. 8 27 February, 2007
MEDICALOPHTHALMOLOGY
Special Types of Contact Lenses
Lovely Sharma, Parul Sony MD
This article provides a brief overview of special types excellent visual quality but adaptation time is long and
of contact lenses – contact lenses feel remains in the eye.
(1) Toric contact lens Hydrogel toric lenses were developed to provide
(2) Presbyopic contact lens optimum visual acuity and comfort to the patient with
(3) Therapeutic contact lens
astigmatism. These lenses are useful for correcting corneal
Astigmatism refers to the optical aberration that or lenticular astigmatism or a combination of the both.
occurs when light is refracted by non-spherical surfaces, Type of Toric Lenses
resulting in ‘Not a Point Focus’.
Corneal toricity is the prime contributor to an 1. Back toric– Central posterior surface has different radii
astigmatic refractive error, but it can be present in spherical of curvature at two principle meridian and spherical
cornea also astigmatism can occur by tilting of crystalline anterior surface. These lenses can correct only corneal
lens or by retinal surface. astigmatism.
Corneal Astigmatism - It is a measure of corneal toricity 2. Front toric – Central anterior surface has different radii
and is the dioptric difference between two meridians of of curvature at two principle meridians with spherical
cornea as measured by keratometer.
back surface. These lenses can correct total refractive
Internal astigmatism – This refers to astigmatism other astigmatism.
than measured by keratometer. Astigmatism produced by
tilting of crystalline lens, back surface of cornea, topography Fitting of soft toric Contact lenses
of retina. Toric Soft Contact Lenses should be fit by using toric
Refractive astigmatism - This is a total refraction of diagnostic Contact lenses:-
the eye as determined by subjective and objective 1. Select a base curve by converting the mean of
refraction.
keratometry reading to mm & add 0.8 mm.
Providing satisfactory vision and comfortable wear 2. Determine lens diameter by adding 2 to 2.50 mm to the
with contact lens for patients with astigmatism has always
been a challenge. Spherical Modality Material W.C C.T Dia. Power Range (in diaptres) B.C.
hydrogel contact lenses are (%) (mm) (mm)
not very effective in
masking astigmatism above
-0.50 DC One strategy was Yearly Hefilcon 45 0.10 to 14 Core Range 8.3
to fit the Spherical B 0.28
Equivalent power & SPH – Plano to -9.00 (till -6.00 in 8.6
although some patient’s 0.25 steps) 8.9
found this acceptable, but CYL– -0.75 to -3.25 (in 0.50 steps)
mostly patients do not Axis-90, 160, 170, 180, 10, 20
satisfy.
Corneal astigmatism is Non Core Range 8.3
corrected by Hard/Semi- SPH – Plano to -9.00 ( till -6.00 in 8.6
Soft Contact Lenses. Rigid 0.25 steps) 8.9
gas permeable (R.G.P) Axis – 70, 80 , 100, 110
Contact lenses can correct
up to - 4.0 DC & provides
horizontal visible Iris Diameter. (HVID)
Venu Eye Institute & Research Centre, 3. Choose the cylindrical power & axis of trial lens nearest
1/31, Sheikh Sarai, Phase-2, to patient’s spectacles refraction.
New Delhi
After insertion the lens should be allowed to stabilize
for at least 15 to 30 minutes. When evaluating the fit of a
February, 2007 28 DOS Times - Vol. 12, No. 8
Soft toric Lens on the eye, if the lens rotates in a clock wise correction.
Mono vision contact lens
direction, the amount of deviation in degree is added to the Presbyopic contact lens
spectacle axis; if the rotation is anticlockwise, the amount
Highly motivated patient who wants to be spectacles
of deviation in degree is subtracted from the spectacle axis, free and have realistic expectations are ideal for presbyopic
so Left Add andRight Subtract (LARSRule) when the lens contact lens fitting.
assumes its final position, the lens rotation should be less
than 50 on blink.
E.g – Spectacle refraction : 4.00/ -2.25 @ 1800 20/20 Patient’s Selection Criteria
Keratometry value : 42.75 @1800 / 45.00@1000 Patient to be selected
Refractive astigmatism : Corneal astigmatism Motivated patient willing to try new modality.
Internal astigmatism Early presbyopes.
Trial lens parameters: : Nil. Single vision contact lens wearer, needing addition.
Base curve : 2.00/ -2.25 @1800 Unsatisfied patient wearing Mono vision or bifocal
Diameter
Over refraction : 8.60 mm glasses.
Fit assessment : 13.5 mm / 14.50 mm Patient with multiple visual tasks.
Patient interested in occasional and social wear.
Solution : 1.75 DS 20/20
: with blink clockwise Patient to be avoided
Final order Lack of motivation.
rotation of lens 100 Have astigmatism more than -0.75 DC.
: to compensate for 100 C.L Required fine and detailed vision.
rotation add 100 to Types of Presbyopic Contact Lens
Spectacle axis.
: 8.60/ - 3.75 / - 2.25 @ 100 Bifocal contact lenses may be fitted for either
cylindrical axis. Simultaneous vision or Alternating vision.
No movement or very minimal Simultaneous Vision contact lenses –In these types of contact
movement indicates steep fit; a lenses, the rays of light from distant and near sources enter
loose fit is marked by excessive the pupil at the same time. The patient’s brain selects the
random rotation. object of regard.
Stabilizing technique used for Alternating Vision contact lenses – In these types of contact
these lenses is prism ballast. lenses, the lens moves so that the rays of light enter the
pupil through either the distant portion or the near portion
Soft toric contact lenses are of the contact lens.
contraindicated in cases of irregular
corneal astigmatism & lid closure Lens Design
abnormalities.
Bi-focal contact lenses are available in four optical
High spherical astigmatic refraction errors & oblique configuration –
axes – the availability of lenses in these power & axes has Concentric (Annular) type.
increased markedly than then past, but most brands still Segmented type.
have some limitations & it takes longer to get then in clinic. Aspheric (Multifocal,Progressive addition) type.
Non – core powers becomes available in 30 days to 45 Diffractive type.
days. Many brands also increase price when ordering
Contact lenses out side common parameters. Concentric Bi-focal contact lenses – These lenses have two
concentric optic zones of differing powers.
Presbyopic Contact Lenses
Segmented bifocal contact lenses - These lenses have two
There are many options available to correct different optic zones, one above the other.
presbyopic patients. Determining the patient’s requirement
and expectations ensures the success of given modality. Aspheric (Multifocal, “Progressive addition”) contact lenses –
In these lenses power increases gradually from the centre
Options Available to Correct the Presbyopia to periphery.
Reading Glasses
Single vision contact lens with spectacles over
DOS Times - Vol. 12, No. 8 29 February, 2007
Diffractive lenses – In these lenses diffractive optics is until patient becomes comfortable before performing an
used rather than refractive optics to achieve simultaneous over refraction. Never use phoropter to perform this
vision. prescription refining procedure due to the instruments
influence on pupil size. Use only hand held trial lenses
Concentric lenses tend to be more comfortable than under standard room illumination. If near vision is not
segmented bifocal lenses. adequate add plus in steps of +0.25 Ds to non-dominant
eye & to dominant eye if only necessary.
Fitting Procedure of Presbyopic Contact Lens
If distance Vision is not adequate one must either add
Pre – fitting evaluation minus or reduce plus to the dominant eye. If distance Vision
Measure spectacle correction, including addition is still reduced, switch the dominant eye to the lower add.
power. We must give serious consideration to fit new
Establish base line binocular visual acuities at distance presbyopes keeping in mind that no single product works
for all the patient.
and near.
Determine dominant eye at distance. Presbyopic Contact Lenses
Monthly disposable, Simultaneous vision (Aspheric There are many options available to correct
concentric multifocal) presbyopic contact lenses are presbyopic patients. Determining the patient’s requirement
available. These lenses have with two base curves 8.50 and expectations ensures the success of given modality.
mm and 8.80 mm and 14.50mm diameter.
Options Available to Correct the Presbyopia
If the flattest keratometry reading is less than 44.0D Reading Glasses
Select 8.80 mm base curve and if the flattest reading is 44.0 Single vision contact lens with spectacles over
D or greater, select 8.50 mm base curve.
correction.
Addition is available in two powers and “Low Add” Mono vision contact lens
and “High Add”. Low add is intended for emerging Presbyopic contact lens
presbyopes to moderate, offering addition power ranging
from +0.75DS to +1.50 DS High add gives the addition power Highly motivated patient who wants to be spectacles
ranging from +1.75DS to +2.50DS. These lens provide center free and have realistic expectations are ideal for presbyopic
near zone for near acuity and intermediate zone contact lens fitting.
incorporating a gradual power change to the distance
correction peripherally.
Initial lens selection Patient’s Selection Criteria
Start with 8.50mm base curve trial lens for better Patient to be selected
Motivated patient willing to try new modality.
centration and comfort. Early presbyopes.
If insufficient movement, apply flatter base curve (8.80mm) Single vision contact lens wearer, needing addition.
Unsatisfied patient wearing Mono vision or bifocal
Power selection
Choose the lens with the patient’s full distance spectacle glasses.
Patient with multiple visual task.
power. Patient interested in occasional and social wear.
If astigmatism present convert to minus cylindrical
Patient to be avoided
form. Lack of motivation.
Select the spherical equivalent prescription and Have astigmatism more than -0.75 DC.
Required fine and detailed vision.
consider vertex compensation.
If spectacle ADD is +1.50 DS or less Select Low Add. Types of Presbyopic Contact Lens
If spectacle ADD is +1.75 DS to +2.25 DS select Mixed Bifocal contact lenses may be fitted for either
Add. (Low Add on dominant eye, High Add on non- Simultaneous vision or Alternating vision.
dominant eye) Simultaneous Vision contact lenses –In these types of contact
If spectacle ADD is + 2.50 DS and up select High Add.
Optimizing the prescription
After inserting the trial lens, wait for 15 minutes or
February, 2007 30 DOS Times - Vol. 12, No. 8
lenses, the rays of light from distant and near sources enter Initial lens selection
the pupil at the same time. The patient’s brain selects the
object of regard. Start with 8.50mm base curve trial lens for better
centration and comfort.
Alternating Vision contact lenses – In these types of contact
lenses, the lens moves so that the rays of light enter the If insufficient movement, apply flatter base curve
pupil through either the distant portion or the near portion (8.80mm)
of the contact lens.
Power selection
Lens Design
Choose the lens with the patient’s full distance spectacle
Bi-focal contact lenses are available in four optical power.
configuration –
Concentric (Annular) type. If astigmatism present convert to minus cylindrical
Segmented type. form.
Aspheric (Multifocal,Progressive addition) type.
Diffractive type. Select the spherical equivalent prescription and
consider vertex compensation.
Concentric Bi-focal contact lenses – These lenses have two
concentric optic zones of differing powers. If spectacle ADD is +1.50 DS or less Select Low Add.
If spectacle ADD is +1.75 DS to +2.25 DS select Mixed
Segmented bifocal contact lenses - These lenses have two
different optic zones, one above the other. Add.
Aspheric (Multifocal, “Progressive addition”) contact lenses – (Low Add on dominant eye, High Add on non-
In these lenses power increases gradually from the centre dominant eye)
to periphery.
If spectacle ADD is + 2.50 DS and up select High Add.
Diffractive lenses – In these lenses diffractive optics is
used rather than refractive optics to achieve simultaneous Optimizing the prescription
vision.
After inserting the trial lens, wait for 15 minutes or
Concentric lenses tend to be more comfortable than until patient becomes comfortable before performing an
segmented bifocal lenses. over refraction. Never use phoropter to perform this
prescription refining procedure due to the instruments
Fitting Procedure of Presbyopic Contact Lens influence on pupil size. Use only hand held trial lenses
Pre – fitting evaluation under standard room illumination. If near vision is not
Measure spectacle correction, including addition adequate add plus in steps of +0.25 Ds to non-dominant
eye & to dominant ey e if only necessary.
power.
Establish base line binocular visual acuities at distance If distance Vision is not adequate one must either add
minus or reduce plus to the dominant eye. If distance Vision
and near. is still reduced, switch the dominant eye to the lower add.
Determine dominant eye at distance. We must give serious consideration to fit new presbyopes
keeping in mind that no single product works for all the
Monthly disposable, Simultaneous vision (Aspheric patient.
concentric multifocal) presbyopic contact lenses are
available. These lenses have with two base curves 8.50 Therapeutic Contact Lenses
mm and 8.80 mm and 14.50mm diameter.
Bandage contact lenses (B.CL) are therapeutic devices
If the flattest keratometry reading is less than 44.0D that are used to treat a range of external ocular surface
Select 8.80 mm base curve and if the flattest reading is disorders primarily affecting the cornea and the adjacent
44.0D or greater, select 8.50 mm base curve. ocular tissues.
Addition is available in two powers and “Low Add” Bandage contact lenses have many uses for corneal
and “High Add”. Low add is intended for emerging rehabilitation; they most frequently function as a
presbyopes to moderate, offering addition power ranging mechanical barrier for corneal protection from the lids,
from +0.75DS to +1.50 DS High add gives the addition power lashes and scar tissue. B.CL enhance corneal surface healing
ranging from +1.75DS to +2.50DS. These lens provide center in condition such as basement membrane disease,
near zone for near acuity and intermediate zone recurrent corneal erosions or non healing ulcers and
incorporating a gradual power change to the distance epithelial defect. These lenses are invaluable for managing
correction peripherally. pain associated with conditions such as corneal abrasions,
DOS Times - Vol. 12, No. 8 31 February, 2007
bullous keratopathy, and filamentary keratitis. B.CLworks indicated in cases such as severe corneal thinning, small
as sealant and assist in sealing leaky wounds after cataract perforations and leaking wounds where the lens tends to
surgery, penetrating keratoplasty or glaucoma filtering act as a splint. In addition because of the increased rigidity
surgery and also small corneal perforations. and stability in comparison to a high or a low water
content lens, the lens may serve to centre better in the
Principles of Therapeutic Contact Lenses presence of significant corneal irregularities.
B.C.L is a Plano, monthly disposable, extended wear
c. Low water content lenses:
contact lens. More recently, bandage contact lenses are
increasingly being used as a medical and surgical adjunct. Are indicated in eyes with minimal inflammation and
The hydrogel contact lenses by way of their lens properties dry eye states. Can be used as an adjunct in cases of
allow for fluid absorption and therefore serve as a drug cyanoacrylate tissue adhesive applications and in cases of
delivery system. disorders of the lids such as trichiasis causing trauma to
the epithelium.
In cases of surface irregularities, application of a contact
lens allows for a spherical refractive element at the anterior Guidelines for Fitting of the Contact Lens
surface and may therefore, serve to improve the vision.
In therapeutic contact lens fitting, keratometry is not
Lens Materials of significant as the cornea is irregular and grossly distorted
in a significant number of cases. Fitting is therefore, most
Hydrogel materials often carried out on a trial basis. The lens parameters which
Therapeutic hydrogel contact lenses are chiefly made are most critical for fitting include the diameter and the
base curve of the lens as these influence the centration and
up of polymers of cross linked 2 hydroxy ethyl the stability of the lens on the eye.
methacrylate (HEMA). By cross linking with polymers such
as methylmethacrylate, vinyl pyrolidone, glycery- Start the initial fit with universal base curve (8.40mm)
lmethacrylate and diacetone acrylamide material and 14.00 mm diameter. The lens should be allowed to
properties such as the lens wettability, oxygen settle on the eye for a minimum of twenty minutes. An
permeability etc are improved. optimal fit should be a well centered lens on the eye
covering the cornea and the limbus adequately.
The choice of a particular hydrogel lens i.e either a
high or low water content lens, thick or a thin lens depends While it is important to ensure that a therapeutic
on the underlying ocular pathology for which it is contact lens does not move much on the eye, a movement
employed. Therapeutic contact lenses need to be worn on of approximately 0.5 mm with each blink is required to
an extended wear schedule for a considerable period of allow for tear exchange and clearance of debris from beneath
time; therefore problems related to hypoxia, lens deposits the lens. If lens movement is less than 0.50 mm or does not
and microbial contamination will still continue to affect move at all, examiner need to select flatter base curve or
this mode of therapy. reduced diameter.
More recently, disposable Silicon hydrogel lenses have Following the first assessment of the lens fit, it is
been used as therapeutic lenses and the results were generally preferred to re examine the patient 30 to 60
favorable. minutes later to assess if there are any changes in the lens
fit. To ensure that there is no undue stress induced by the
Selection of Lens Material contact lens on the ocular surface and to assess the progress
While the selection-of a lens material is primarily of the condition a follow up visit at 24 hours is critical.
Thereafter, follow up visits are scheduled depending on
dependant on the corneal pathology for which it is the type and the severity of the condition which
employed, few general principles can be applied: necessitated the use of a therapeutic lens.
a. High water content lenses Suggestive Readings
Indicated for disorders which necessitate as minimal
• Visser ES, Visser R, Van Lier HJ. Advantages of toric scleral
epithelial disturbance aspossible, e.g. epithelial defect. The lenses. Optom Vis Sci . 2006;83:233-6.
lenses also perform well in eyes with severe
• Ruston DM. The challenge of fitting astigmatic eyes: rigid gas-
Corneal and anterior segment pathology, where they permeable toric lenses. Cont Lens Anterior Eye. 1999;22 Suppl
tend to be more comfort-able. 1:S2-13.
b. Medium water content lenses
May be the lens of choice for drug delivery. Also
February, 2007 32 DOS Times - Vol. 12, No. 8
MEDICALOPHTHALMOLOGY
Artificial Eye
Richa Tomar, Neelam Asthana MS
Since the beginning of the civilization men and women they are also known as "stock eyes". These are very cheap
have been using artificial means to enhance their & are made of low grade plastic. They have to be selected
personality and looks. Use of artificial eyes dates back to by trial and error method. They are made in large
5600 B. C. Mummies were fitted with silver or golden quantities with different shapes, sizes and colours. They
artificial eyes. Ambroise Pare, pioneer of modern artificial are easily available but cannot cater to the needs of all
eyes used glass and porcelain in 1557 to make them. Glass patients. Readymade eyes have drawbacks like poor colour
remained the main material and Germany was the major matching, poor centration, collection of discharge behind
supplier till the World War - II. After that, experimentation the prosthesis and reduced movements as the front surface
of socket does not matches with the back surface of artificial
Fig.1: A 21 year old female with right anophthalmic socket. eye. In the long run they cause sagging of lower lid as the
weight remains on lower fornix and in extreme cases a
Fig.2: The same patient with custom made prosthesis. contracted socket. Hence, the role of readymade eyes is
becoming limited around the world.
with plastic material started. Now poly methyl metha
acrylate ( PMMA ) is the most widely used material because With increasing awareness of cosmesis, there is now a
it is biocompatible and non allergic. The technology of need that an anophthalmic socket should be given an ocular
fabricating eyes from plastic has become so advanced that prosthesis which is well fitting and colour matched to
it is now possible to custom design any type of ocular resemble the fellow eye. This problem is solved by using a
prosthesis to cater to a wide variety of patients. custom made ocular prosthesis.
An artificial eye is a device which is used to replace the Custom made artificial eyes are made by taking an
volume of the empty socket and to restore the appearance impression of the patient's eye socket. These are made for a
of a natural eye. An ocular prosthesis can not provide vision particular person and give good cosmetic results by
but can provide such near normal looks of an eye that it is replacing the volume, providing good motility to
difficult to make out the difference. prosthesis and maintaining contour of lids. The size of
Artificial eyes are of two types palpebral fissure and colour of the prosthesis match with
the fellow eye as it is hand painted. Since the prosthesis
Readymade artificial eyes are available in market and fits very well in the socket there is no potential space
between the ocular surface and the prosthesis hence there
Venu Eye Institute & Research Centre is better motility and there is no collection of discharge.
1/31, Sheikh Sarai - II There is no sagging of lower lid as the custom made
New Delhi - 110019 prosthesis does not put undue weight on the lower lid.
Because of these advantages the custom made prosthesis
can be worn for a longer period.
These are made of high density medical grade PMMA.
Optical clarity is the main feature of this plastic. It is
unbreakable and non-toxic.
Need for an artificial eye
Out of every 10,000 new born babies one child is born
without an eye. There is also a significant number of
persons who have lost an eye due to trauma, infection or
surgical removal. People with disfigured eye face
psychological and cosmetic challenges in life. They are
unhappy with their looks and suffer from lack of confidence.
To rehabilitate them an Ocularist plays an important role
along with an Oculoplastic surgeon. Custom designed
artificial eyes can not only make these people look normal
but also raise their confidence level.
DOS Times - Vol. 12, No. 8 33 February, 2007
Fig.4: A 27 years old male who underwent evisceration with ball implant
in the left eye.
Fig.3: Various st ages in the making of custom made prosthesis.
Making of an artificial eye Fig.5: The same patient with custom made prosthesis.
First of all an impression of patient's eye socket is taken Fig.6: An elderly p atient with phthisis of right eye.
and a wax model is made. The wax model is tried in the
patient's eye socket and sculpted for opening of palpebral Fig.7: The same patient fitted with custom made prosthesis.
fissure, size and shape of socket and contour of lids. Closure
of lids is checked so that the lower lid does not sag. Then being referred to an ocularist.
centration for corneal position is done. From the wax model 3. Patients having congenital microphthalmia/
a copy in white PMMA is made. Then it is hand painted to anophthalmia
match the colour of the fellow eye so that it gives a life like
effect to the prosthesis. After this a layer of transparent In congenital microphthalmia / anophthalmia it is
PMMA is applied to save the colours. Finally it is polished important to refer the infant to an ocularist as early as
to make it smooth and shiny. possible to start fitting of the conformer or prosthesis to
help stimulate bony orbital growth. Fitting of a series of
The key to achieving the best cosmetic result is that increasingly larger prosthesis helps to form an adequate
there should be continuing education and communication socket.
between the patient, oculoplastic surgeon and ocularist. 4. Patients having problems with an existing prosthesis
When each member of the team is aware of the expectations,
talent, capabilities and constraints of the others, only then Patients using artificial eye may have problems either
the best final result can be achieved. with the surface of the prosthesis or its fitting.
A. Poor fit
An ocularist plays a very important role in proper
making, fitting and care of artificial eyes. Ocularist is a The common reasons for a poor fit are orbital fat
professional trained in fitting and fabricating custom- atrophy, implant migration, continued phthisis or other
made artificial eyes. It is a combination of art and science
and is known as "Ocularistry". The eye care professionals
should be aware of the conditions where the help of an
ocularist is needed so that the patient can be referred to an
ocularist well in time.
Indications
1. Post Operative Patients
After 4 to 6 weeks of surgery (Enucleation / Evisceration)
the patient should be referred to an ocularist for fitting of
an artificial eye provided the inflammation has subsided
completely.
2. Patients with phthisis and atrophic bulbi
If asymptomatic then such patients should be referred
immediately. In case the patient has pain and redness then
he / she should be treated and made symptom free before
February, 2007 34 DOS Times - Vol. 12, No. 8
Fig.8: A 6 years old child with congenital anophthalmos in right eye. Fig.9: Same child with well fitting custom made artificial eye.
changes in the globe. Children will often need more frequent surface deposits.
replacements or enlargements to compensate for growth
and help to stimulate bony orbital growth. With people becoming more aware of their looks and
the facilities provided by eye care centres there is a sincere
B. Surface condition problems effort being made by the eye care professionals in referring
With continuous wear of an artificial eye, there is a needy patients to a dependable ocularist. Customized
artificial eye is a big step towards rehabilitation of people
build up of protein film on the surface of the prosthesis. with lost or disfigured eyes. Social and psychological
This should normally be cleaned off by the patient on daily rehabilitation of theses people will go a long way in
basis. The protein build up can become encrusted and enhancing their personality and increasing their
difficult to remove. The ocularist can polish of the stubborn confidence.
DOS Times - Vol. 12, No. 8 35 February, 2007
MEDINEWS
Computer Generated Animation
Saurabh Sawhney DO, DNB, Aashima Aggarwal MS, DNB
Animation comes from the Latin word anima, meaning Flash files are identified as flash movies (with filename
life or soul. Animation is a technique, which, by presenting extension .fla). You can create a blank flash movie by right
a sequence of slightly different images to the observer so clicking on an empty area in a folder, or on the desktop,
quickly that they are merged by the brain into a flow, seeks and following the new menu. Or you could open flash from
to establish the illusion of movement. The technique was the programs list, but remember to give the movie a name
mastered by Walt Disney, who enthralled the world with and save it where you can find it later. Once you have
the antics of an entire array of characters. created a flash movie file and are in the workspace, your
view is something like this.
In the medical sciences, animated sequences have
become a part of life. They are invaluable adjuncts to To begin with, one needs an object that is to be
explaining complex disease patterns and events to patients, animated, and a background to animate it against. So that's
and to doctors who are learning. Animations can often at least two layers w e are talking about. Now, on your
illustrate clearly and with precision concepts that the monitor, look at the upper left corner, where it says Scene1.
camera cannot catch. Even theoretical concepts like an Below this is written Layer 1, and a bit further down is a
embolus blocking the coronary artery, for instance, can be plus sign. Click this sign, and a layer is added above layer
simulated by means of an animated film. Apart from clarity 1. The figure below captures part of the screen now.
and accuracy, animation is also an art form whose visual
impact can be stunning.
In the earlier days, a master artist used to draw what
were called key frames, which depicted the beginning and
end of a particular movement, for example a smile. Junior
artists would then draw a number of frames in between,
which would all be compiled and rapidly flitted across the
screen, producing an effect of someone smiling. Often, the
background would remain stationary, and the smile
sequence drawings would be on transparent cellophane
paper, so that they could be placed over the background
drawings and then photographed, frame by frame
painstakingly. At the end of it, you would get a smiling
face over a background. This was called working in layers.
The principles are still valid today, but the actions are
now performed in a much more stylish manner.
Professional animation software does most of the work,
and the animator needs only to know what orders to give.
One of the most popular software for developing 2-D
animation is Flash (Adobe). It allows one to work in layers,
does the in-between drawings itself (called Tweening), and
generally makes life a lot easier. We shall be discussing
with reference to Flash version 5.0.
Let us look at the basic principles of working in a Flash
environment. First up, you need a computer that has Flash
loaded onto it, preferably with a dedicated graphics card,
and a good quality coloured monitor. A high speed
processor and a good RAM are preferable, but not essential.
Insight Eye Clinic You will notice that layer 2 is selected (marked by black
Rajouri Garden, New Delhi colour). This means that whatever you now draw will be
E-mail: [email protected] drawn in layer 2. So let's draw a ball. To do this, pick the
February, 2007 36 DOS Times - Vol. 12, No. 8
oval tool (by clicking on it). It is placed on the left side of the Now we need a background against which to animate
screen, on the palette marked “Tools”. See red arrow in the the ball. This background needs to be in a separate layer so
figure given below. Now, click in the white central area of that it stays stationary whilst the ball moves. First select
the screen (the workspace), and drag the mouse to form an layer 1 by clicking the part of the screen that says layer 1,
oval. Once it is about 3-4 cm in size, release the mouse just below the selected layer 2. As you click, layer 1 becomes
button, and you have a blue coloured ball. If you don't like black while layer 2 becomes the default colour. Now, use
the ball, then go to edit and undo the action. Flash is a very the minifying lens to adjust the workspace so that all
forgiving program and allows a lot of undo, even if you've corners are easily visible. If you have minified too much,
saved your work in between (100 undo levels by default, use the magnifier button. It is just next to the minifier and
but can be set up to 300 undo levels). is marked with a plus sign. The options to magnify and
minify are available only after you have picked up the tool
from the Tools palette.
Once the workspace is set to your liking, pick up the
rectangle tool, which is located just to the right of the oval
tool, which we used to draw the ball. The rectangle needs
to be a different colour from the ball to provide contrast, so
let's look into the Color palette now. This is located below
the Tools palette and the View palette, and has two parts.
The upper one is Stroke colours, while the lower one is Fill
colours. The former refer to outlines, while the latter refer
to colour inside closed areas. Having picked up the rectangle
tool, click the fill portion of the palette, where there is a
blue patch of colour. Refer to the figure below; this is what
your screen will now look like:
Now, if you've pressed the right buttons, you should
have a display like this. You can always decrease the
magnification to get better perspective (use the magnifying/
minifying lens in the tools area, near the bottom, see green
arrow in the above figure).
DOS Times - Vol. 12, No. 8 37 February, 2007
Note that the rectangle tool is selected, as is layer 1. In
this colour palette, you can choose any colour by just
clicking with your mouse pointer, which, if you notice,
will acquire a very different shape, called an eyedropper. It
will pick up colours from not just the palette, but almost
any part of the screen. Use the eyedropper tool to pick up
the centre of the green coloured circle, as marked by the
blue arrow.
This is a predefined gradient and produces a rather neat
effect in our rectangle to be. To make the background, just
go to the top left corner of the workspace, (marked in the
above figure by a small red arrow), click and drag the mouse
to the bottom right corner, and leave it there. If you have
followed the steps correctly, your display will look like
this:
the popup menu that appears, the topmost option reads,
create motion tween. Click this. The layer 2 frames section
looks like this now.
The entire workspace, which was white to begin with, We have just instructed the computer to create a 'motion
is now covered with a green to black gradient. tween', which means that we have asked it to draw the
intermediate frames between two keyframes. We have
Now our first animation is all set in its basic elements. already drawn the first keyframe, defining the initial
We have the object to be animated and the background in position of the blue ball. Now we need to insert a second
separate layers, and the first keyframes are already drawn keyframe, defining the final position of the ball. This is
by you. Look at the frames section, just to the left of the done by right clicking at frame 30 in layer 2, and then
layers section. There are two black dots in frame 1, selecting 'insert keyframe', like this.
corresponding to each layer. Now we need to add more
frames, over which the action will take place. This is just a Another dot appears at that frame, signifying that we
little bit tricky. In the frames section, you will notice have added the second keyframe. Now pick the arrow tool
numbers that go 1, 5, 10, 15, 20 and so on. These refer to (marked with a green arrow), located at the top left corner of
frame numbers. Position the cursor below the number the Tools palette. Using this, position the ball somewhere
marked 30, in line with layer 2, and click the right button near the centre of the background. The screen looks like
of the mouse. On the menu that pops up, click 'Insert frame'. this next page:
The screen will now look like this.
Now you are ready to see the result of your animation.
Notice that our beautiful background is nowhere to be Press Enter, and watch the ball move from the top left corner
seen. This is rectified easily. Just move the cursor to below of the screen to the centre.
number 30, but in line with layer 1, and 'Insert frame' like we
did earlier. That restores the background.
Now, once again, position the cursor somewhere
between frames 1 and 30, but in layer 2, and right click. On
February, 2007 38 DOS Times - Vol. 12, No. 8
This is a short animated film, with a very simple have to provide the keyframes. Work in layers. Every
animation, but it illustrates the powerful processes that separate moving object has to be in a separate layer. Once
go into making extremely complex movements. Remember, keyframes and layers are understood, you are on firm
the computer will draw the intermediate frames, but you ground as far as fundamentals of animations are
concerned.
If you are happy with the movie, you can export it as
an .avi movie, which can be played in the windows media
player, inserted into powerpoint, edited by movie editing
software such as Adobe Premiere, and is generally a helpful
format. It is worthwhile to note that as you export (the
path is File-Export Movie), Flash offers you the option of
compressing your final output. Do use compression, as it
significantly reduces file size without really affecting
quality.
We have just scratched the surface in so far as 2-D
animation is concerned, but we have covered several
important principles. We shall be conducting a workshop
on Flash animation in the DOS annual meeting in April
2007, and those interested in a more practical and hands
on session are invited.
DOS Times - Vol. 12, No. 8 39 February, 2007
HARDWAREHINTS
High Speed Vitrectomy
Vinod Aggarwal MS, Neha Goel MBBS, Meenakshi Thakar MD, FRCS
Relief of vitreoretinal traction by modification of Diathermy
vitreous has revolutionised the approach to retinal Machines should have diathermy for endo and exo
detachment. The technique was evolved at Bascom Palmer
institute in hands of Kasner and Machemer. In 1970, diathermy for selective burn placement on retina and
Machemer and Parel and collegues designed an instrument sclera. Diathermy function should also be available during
for vitreous removal named VISC, for vitreous-infusion- priming function to avoid any delays.
suction-cutting. Later illumination was provided by
optional fibroptic sleeve. The greatest subsequent Air-fluid Exchange
technologic improvement has been separation of multiple There should be control of preset and actual infusion
functions into separate units, each with its own site of
entry through pars plana: infusion, illumination and pressure of air in pressure range of 5-95 mmHg for air fluid
aspiration and cutting. Additional sophisticated exchange.
instruments combined with advent of high speed
multifunctional machines have made certain retinal Fragmentation
diseases treatable which were not few years back. The Fragmentation mode provides smooth, efficient
A good vitrectomy machine should offers following ultrasonic fragmentation and vacuum using a lightweight
facilities hand piece connected to the surgical system with an electric
cable and vacuum tubing.
High Speed Vitrectomy
Four different fragmentation modes exist: Linear,
A standard high speed cutter has cutting frequency of Momentary, 3D Frag and Fixed Frag. These multiple modes
upto 2500 into/min. High speed cutting offers reduced help accommodate surgeon preference.
traction and increased stability while working close to
retina. Machine should support both pneumatic and The Linear Fragmentation mode is specifically
electric drive for pneumatic and electric vitrectomies. It designed to control and emulsify subluxated lenses, and
should be usable in single cut, fixed and linear cutting the new 3D Fragmentation mode allows simultaneous
control. New horizontal cutting probes have a radial control of ultrasonic power and vacuum
reciprocating action to minimize turbulence or fluttering
of tissues (cutting blade moves from left to right across the Automated Infusion Pressure
port). Digital infusion pressure provides immediate response
3D Technology to increase or decrease IOP and gives the surgeon precisely
controlled pressurized infusion for chamber stability. The
This allows the operator to simultaneously change cut surgeon-elevated infusion feature provides both ease-of-
rate and vacuum which provides way to easily change use and control of infusion pressure via the foot pedal to
parameters as needed throughout the surgery. instantly control intraocular bleeding. Digital control
eliminates manual raising and lowering of the IV pole,
which is required with traditional gravity infusion method.
Fiber Optic Illuminator Viscous Fluid Injection
Pneumatic drive for Viscous Fluid Injection with Fixed
Machine should provide simultaneous use of two or
three illumination ports. Light source is generally a or Linear controlled pressure injection with a pressure
Halogen bulb and automatic switch should occur to second range should be provided for injecting silicon oil if required.
lamp when first lamp fails. There should be integrated
heat protection filter for cold light and UV/IR filtering. Viscous Fluid Extraction
Linear vacuum controlled viscous fluid extraction.
Vitreo-retina Unit Scissors
Guru Nanak Eye Center The Scissors mode provides cutting capability using
Maharaja Ranjit Singh Marg, New Delhi
February, 2007 40 DOS Times - Vol. 12, No. 8
pneumatically or electrically powered scissors controlled Fig.2 Fig.3
by the foot switch in three modes: Proportional, Multi-cut
and MPC.
Automated MicroScissors and Forceps facilitate
segmentation, delamination and en block scissors
techniques
Following are some of the currently available machines
DORC (Dutch ophthalmic research center)
The D.O.R.C. Associate is an advanced ophthalmic
system that integrates both a Peristaltic and Venturi pump,
allowing surgeon to independently select either pump
mode for Phaco or Vitrectomy procedures. (Fig.1)
Associate is updated model with touch screen
technology
Fig.2: ACCURUS Surgical System Fig.3: Millennium microsurgical
system
Following special instruments are required for the
surgery
Fig.1: D.O.R.C. Associate Indications of 25G vitrectomy
Epiretinal membrane peeling,
ACCURUS Surgical System (Alcon) Macular hole surgery
Provides 3D technology advancement and surgeon Retinal detachment with minimal PVR
BRVO sheathotomy
control to make posterior, anterior and combined surgeries Vitreous hemorrhage
more efficient. (Fig.2) Endophthalmitis.
Smaller eyes of children
Millennium microsurgical system (Bausch and Lomb)
High speed Vitrectomy with 600-1500 cuts/min (Fig.3)
Sutureless vitrectomy Limitations of 25G vitrectomy
Previously scarred operated eyes, trocar may bend.
TSV system 25-gauge developed by Fujii et al. it has
following advantages
Selfsealing transconjunctival sclerotomies
Minimizes surgically induced trauma
Improves operative efficiency
Hastens postoperative recovery.
No sutures are required at any conjunctival or scleral
opening site.
But due to the smaller size, the infusion and aspiration
rates are reduced may prevent the incorporation of
multiple functions in one port.
DOS Times - Vol. 12, No. 8 41 February, 2007
Highly myopic patients,wound
may not close
Difficult to infuse silicon oil
Dense fibrous proliferation
Increase flexibility may not be
able to control eye positions
Sutureless opening serving as
entry of bacteria.
Wound leaks
Eckardt 23-Gauge Vitrectomy System
Tensile strength of 23-gauge
instruments is similar to current 20-
gauge instruments
No limitation to the type of
surgical procedure
Conjunctival Stamp compresses
the conjunctiva into the scleral bed
and provides a fixation point from
which to make the entry into the eye.
Once the 23-gauge incision is Steps showing port preparation in 25G vitrectomy
made, the stainless steel cannulas are The twin light forceps clip onto the twin light
gently placed into the wound site, allowing for a very
chandelier, widening the twin fiber optics to a precise
smooth, non-traumatic insertion. distance of 6mm.
Twin Light Chandelier System The chandelier is placed through the sclerotomies
It is a Wide angle illumination to enhance visualization The forceps are released allowing the fiber optic tips to
and accommodate a True bimanual surgical technique. Two regain their non-parallel position.
separate 25-gauge fiber optics eliminates the shadowing
effect. To summarize, the advent of high speed vitrectomy
machines with advanced features combined with use of
Procedure newer wide angle viewing systems and smaller ports has
Neptune stiletto facilitates 2, 25-gauge sclerotomies, made modern day vitreous surgery extremely safe.
6mm apart.
February, 2007 42 DOS Times - Vol. 12, No. 8
PEEPINTHEPAST
Ernst Fuchs
Lt Col Rakesh Maggon, Col JKS Parihar, Lt Col V Mathur
Ernst Fuchs, son of an the then new technique of using large print for material
ophthalmologist, was born suitable for students and small prints for that which he
on 14th June, 1851 in Vienna, felt was important for people who were continuing to
Austria. He studied medicine study ophthalmology as a postgraduate exercise.
in Vienna where he was a
pupil of Ernst von Brücke George Joseph Beer (1763-1821) was the first professor
(1819-1892), Christian Albert of ophthalmology in Vienna and he was succeeded by
Theodor Billroth (1829-1894), Fuchs' teacher, Von Arlt, who rapidly made Vienna the
and Carl Ferdinand von Arlt centre of the world for this specialty. Fuchs added to this
(1812-1887). Even as a student renown and an idea of the number of patients he saw may
he held a position as assistant be gauged from an article in 1897 on retinitis circinata
at the physiological institute where he states that of 70,000 patients who had been seen
during the 7.5 years in his clinic, he had only seen 11
in Innsbruck. patients with this rare condition.
He obtained his doctorate in 1874 and began as an The Shah of Persia, Nasr-ed-Din, sent his favourite wife,
apprentice of surgery under Billroth. From 1876 to 1880 he diagnosed as having a cataract, together with several other
women with cataracts, to Fuchs for his treatment. When
was an assistant to the oculist Von Arlt, then the professor Fuchs examined her he found that she had glaucoma and
of ophthalmology in Vienna. VonArlt was a man for whom there was nothing he could do, but he was able to remove
the cataracts from the women who accompanied her. The
Fuchs had the greatest admiration and respect throughout Shah could never comprehend how Fuchs could restore
his life. From 1880 to 1885 Fuchs was professor of the sight of servants and could do nothing for his favourite
wife.
ophthalmology in Lüttich, and in 1885 succeeded Eduard
Jaeger Ritter von Jaxtthal in the chair at Vienna as Professor Fuchs was a great traveller and also enjoyed walking
on his vacations in out-of-the-way places. Besides his
of ophthalmology and held this position until 1915. clinical descriptions of diseases of the eye, his accurate
recording of the various afflictions of the retina and his
Fuchs' earliest work consisted of an examination of interest in histopathology, he also was an innovator in
the pathology of conditions of the eye and this approach surgery. Largely through his efforts the age-old custom of
enabled him to publish in 1881 an analysis of sarcoma of a patient after a cataract operation being kept in bed with
the uveal tract based on 259 patients. In the same year he both eyes covered in a dark room for a week before the
was appointed to the chair of ophthalmology in the dressings were changed, was abandoned. He introduced
University of Liege. early ophthalmoscopic examinations after these operations
which enabled him to discover that choroidal detachment
In 1882 Fuchs emphasised the difference between the was far more common than had previously been imagined.
acquired atrophic crescents and congenital crescents due
to a defect in the development of the choroid which usually At the outbreak of World War I Fuchs was a very
occurs at the lower margin of the optic disc - a condition wealthy man with a sizeable practice, and he lived
now often referred to as Fuchs coloboma. In 1885 he accordingly. But after the war, due to the inflation that
returned to Vienna, publishing an important paper on the ensued, he became quite hard up. He could do little about it
anatomy of the iris, and in 1889 the first edition of his but was helped greatly by his friends and admirers, who
textbook of ophthalmology, Lehrbuch derAugenheilkunde. enabled him to undertake a lecture tour to the United States,
His Textbook of Ophthalmology was regarded as the "bible Spain, Egypt and Asia Minor.
of ophthalmology" for more than 50 years. Decades after
Fuchs' death, ophthalmologists around the world relied A tall man with a slight stoop, Fuchs embodied
on this definitive text. This book, taken from his lectures, equanimity maintaining a calm and unruffled exterior and
was a classic in its time and published in all European never became angry or impatient. He spoke excellent
languages as well as Japanese and Chinese. Fuchs employed English and maintained his investigatory curiosity right
to the end, when he died of angina pectoris on November
Department of Ophthalmology 21, 1930, in Vienna.
Army Hosp (R&R),
Delhi Cantt., New Delhi
DOS Times - Vol. 12, No. 8 43 February, 2007
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