3. Subcategorisation of Stage-4 (A & B) & stage-5 (A, B & C). 4. Normal to Plus disease is now recognised as a continuous spectrum with Preplus in between (venous dilatation & arterial tortuousity insufficient to be categorised as Plus disease. 5. APROP is now called AROP, because Aggressive ROP can occur in anterior zoneIII also. Tip-302...... Bilateral asymmetric diabetic retinopathy, persisting for over 2 years in a patient may indicate an underlying serious systemic disease like Carotid occlusive disease (causing Ocular ischemic syndrome) However, unilateral ocular diseases, mentioned in Tip-295, may also be responsible for this. Tip-303..... A typical Spectral Domain (SD)-OCT uses/has: 1. 20,000 to 40,000 A-scans/second. 2. Resolution upto 10mn 3. Images 6mm area (continuous imaging unlike Time-Domain). 4. 800-870 nm wavelength. While Swept-source (SS)-OCT uses/has:
1. 1-4 Lakh A-scans/second (improved resolution). 2. Axial resolution of 5mn. 3. Larger scanned area (12mm). 4. Longer wavelength (1050 nm), hence penetration better through hazy media & deeper into choroid through RPE. Thus SS-OCT has better imaging quality & deeper penetration. Tip-304..... Torpedo maculopathy (retinopathy): -Torpedo-shaped retinal lesion is congenital RPE lesion like CHRRPE (see Tip-290). -is unilateral, non-progressive, hypopigmented, horizontally oval lesion, temporal to fovea with tip pointing towards foveal centre. -Mostly coincidental finding. -Rarely CNVM can develop. Tip-305...... "Featureless retina" in diabetic retinopathy (DR).... is neovascularisation occuring in benign looking DR in the absence of any significant soft exudates, hemorrhages & IRMAs, thus misleading the clinician. FFA immediately clinches the diagnosis and shows highly ischemic retina (extensive CNP areas).
Suspect it clinically, if one notices highly attenuated arterioles, thinned & atrophic looking retina, asymmetric appearing DR (actually not asymmetric as revealed on FFA- which must be done in any doubt). Tip-306...... Carotid occlusive disease causing Ocular ischemic syndrome can present as eye or browache & deteriorating vision. TIAs & amaurosis attacks may occur. Fundus may show retinal arteriolar narrowing, venous dilatation, micros, retinal hemorrhages, soft exudates, neovascularisation & even arteriolar pulsations. Patients commonly suffer from heart attack (IHD) or brain stroke (CVA). Treatment is anti-platelet therapy & Carotid endarterectomy. Tip-307....... Few facts about ROP .... -Think of Aggressive ROP (AROP), if pupil is not dilating. -Indications for ROP screening in India is: birth weight of </= 2000 grams or Gestational age of </= 34 weeks (Internationally it is 1500 grams & 30 weeks).
-Anti-VEGF in ROP (see Tip-131) is considered in Zone-1 ROP, non-dilating pupil & hazy media. FDA has approved Lucentis for ROP in 2019. Tip-308...... Artificial Intelligence (AI) in retinal imaging: Machine Learning (ML) rather than manual analysis filters relevant information from 'Big data'. It detects 'morphological fingerprints' e.g. predicting whether individual patient with drusen has higher risk for developing CNVM. Another example is to detect intra/subretinal fluid on OCT scan on different antiVEGFs treatments by Deep Learning (DL is superior subset of ML). Tip-309...... IRVAN syndrome (Idiopathic Retinal Vasculitis, Aneurysms & Neuroretinitis, 1995): -Rare, bilateral, inflammatory, idiopathic (autoimmune?) syndrome. -Multiple macroaneurysms (knotted/beaded arteries) are the hallmark. -Unlike Eales', (age group similar), vascular sheathing is uncommon, macroaneurysms (>50 mn, microaneurysms are 10-50 mn
sized) in first order arterioles and exudates are common, but treatment is almost similar. Tip-310....... Few important facts about Ocular Tuberculosis (OTB) Also see Tip-167: 1. Most commonly manifests as Tubercular uveitis (TBU), more specifically Tubercular choroiditis (TBC). Different phenotypes exist e.g. Serpiginous like choroiditis (SLC, See Tip-180), Multifocal choroiditis, Focal choroiditis, Tubercular retinal vasculitis (TRV) with perivascular sheathing (same as Eales'). 2. Diagnosis of OTB is mostly presumed, as no single pathognomonic lesion or immunological test is confirmatory. Direct detection of Mycobacterium (only confirmatory test) in tissues is mostly not practical or feasible & has poor yield. 3. Latent TB (no active TB infection) gives positive immunological tests (Mx & IGRA) & PCR, hence strong clinically suspicious lesion is must before starting ATT. 4. No international agreement exists on therapeutic regime & duration of treatment. COTS (Collaborative ocular TB study) is trying to standardize these in collaboration with IUSG & IOIS.
Tip-311..... Reason & remedy for poor fundus image (FI) on fundus camera: 1. Small FI- long working distance between lens of camera and eye. Go closer. 2. White spot in top of FI- lens is too close. Take it away. 3. Dark shadow in top of FI- Lens is slightly lower than the visual axis. 4. Dark shadow in the bottom of FI- Lens is slightly higher than the visual axis. 5. Blue or white flare at the edge of FIAngle of lens needs to be adjusted to avoid corneal reflections. Tip-312....... OCT in general is not meant for peripheral retina; however peripheral retinal imaging is possible with OCT by1. Steered image capture. Heidelberg Spectralis has steerable laser head. 2. Montaging the images. However, both are time consuming (need 20-30 minutes) & significantly reduce the resolution. 3. Optos (Silverstone model)- is full-field Swept-source OCT capturing peripheral retina (beyond vortex ampulla) in single scan (23mm line scan possible, 1mm~5*). For advantages of peripheral OCT, follow Tip-313.
Tip-313...... Some applications of peripheral OCT (i.e. imaging anterior to vortex ampulla): 1. Extent of retinal breaks, detachment & schisis can be exactly delineated. 2. Retinal Tuft commonly misdiagnosed as retinal hole on clinical examination becomes easily differentiable. 3. Small subclinical retinal fluid around lattice degeneration is easily picked up. 4. Vitreo-retinal adhesions or traction around lattice can be easily defined. 5. Masquerades such as retinoschisis and retinal detachment are easily differentiable. 6. Tele-ophthalmology would allow it to be interpreted by remotely placed retinologist. Tip-314...... Cobblestone (Paving stone) degeneration is peripheral chorioretinal degeneration seen as multiple, depigmented, well defined, atrophic punched out areas mainly in inferior retina & is usually an incidental finding requiring no treatment. Tip-315..... Many recent studies have demonstrated 2 times increase in rate of diabetic retinopathy (DR) detection with UWF fundus camera (100-200° of retinal imaging) & have shown that peripheral NPDR lesions are associated
with 4 times increased risk of disease progression in next 4 years. Tip-316...... Many Non-mydriatic digital fundus cameras (NMFC) are now available including those from India (Remidio & Forus). Advantages of NMFC include: 1. saves time of dilatation. 2. Eliminates need for bright lights & flash making it comfortable for patient. 3. No fear of precipitating acute ACG attack at the remote place during community screening. 4. Some are also portable, telemedicine compatible & have artificial Intelligence (AI). 5. Useful for community outreach programs and screenings in glaucoma, DR & AMD. Locally trained personnel can click the picture & send for interpretation by remotely placed ophthalmologist. Tip-317....... Postoperative choroidal detachment is usually self limiting and resolves within days to two weeks, if the cause (hypotony and inflammation) is removed. Cycloplegics and steroids help.
Tip-318....... Retinoblastoma can occasionally occur in older children (above 5 years of age) commonly masquerading as inflammatory disease (uveitis/endophthalmitis), but it remains painless and without congestion. Many of these are of diffuse infiltrating type. Tip-319...... Choriocapillaris are better studied on Sweptsource OCTA and not on ICGA, which visualises the larger choroidal vessels better. Loss of choriocapillaris (as in AMD) deprives nutrition to RPE and outer retina causing ischemia with greater likelihood of drusen and CNVM. Tip-320..... To be safer, if Anti-VEGF is injected as vitrectomy adjunct for fibrovascular proliferation in TRD, surgery must be performed within 4 days of injection; since rapid involution of fibrovascular proliferation can lead to progression of TRD. Tip-321.... Fancy sign described on SD-OCT is the 'Flying saucer sign' in HCQ (Hydroxy chloroquine) toxicity, in which there is loss
of hyper-reflective Ellipsoid layer in perifoveal area but thickening of underlying RPE-Bruch's complex. Tip-322..... No Stem cell treatment for any retinal disease (e.g. ARMD, Retinitis pigmentosa, Stargardt) is FDA approved till today & at best be considered experimental. Greatest potential risk in stem cell treatment anywhere in the body is that changing the nuclear structure of cell can lead it to multiply uncontrolled and cause cancer. Tip-323....... As per COTS group recommendations, among many Tubercular uveitis (TBU) phenotypes (see Tip-310), Serpiginous like choroiditis (SLC) & Tuberculoma are highly suggestive of tubercular etiology. Hence, consider starting the ATT even if one immunological test (Mx or IGRA) is positive. Add systemic steroids if no systemic infection exists. By contrast, Multifocal or Focal choroiditis are less likely to be of tubercular etiology & require both immunological & radiological tests to be positive before starting ATT.
Tip-324...... Feeder vessel photocoagulation (only of feeding arteriole & Never of vein) is now no more recommended for sea-fan neovascularisation (e.g. in Eales', Sickle cell disease); rather Scatter laser is done surrounding the sea-fan. Tip-325...... Optociliary shunt (Retinochoroidal shunt) vessels are not the shunt (arteriovenous communications bypassing capillary network) vessels in literal sense, but are actually the 'collaterals' formed on the optic nerve head (e.g. in CRVO) and join retinal venous circulation with peripapillary choroidal veins. Collaterals are always formed from dilatation of pre-existing capillary network. Tip-326..... Before undertaking cataract surgery, always remember the rare possibility of posterior capsular tear in any patient who has received the Intravitreal injection. Especially suspect, if there are linear opacities in lens or the cataract has progressed rapidly. If doubtful, treat it like posterior polar cataract i.e. avoiding hydrodissection & doing optic capture of IOL.
Tip-327..... Intravitreal injection if planned during cataract surgery, is best injected after the IOL is implanted but before the viscoelastic removal. Tip-328...... Large submacular (subretinal) hemorrhage (SMH) most commonly occurs due to Polypoidal choroidal vasculopathy (PCV) besides CNVM & RAM (Retinal arterial macro aneurysm). Subretinal hemorrhage is more & faster damaging to photoreceptors than sub-RPE hemorrhage. Subretinal hge is bright red unlike darker blood in sub-RPE. For treatment of SMH, follow Tip-329. Tip-329...... Treatment of Submacular hemorrhage (SMH): Mono or combined therapy as follows1. Anti-VEGF injection alone if SMH is small. 2. Pneumatic displacement by expansile gas with anti-VEGF & with/without rTPA (recombinant TPA). Patient lies face down for 3-5 days.
Tip-330.... Intraretinal fluid (IRF) is more damaging to retinal structures & has worse visual acuity than subretinal fluid (SRF) IRF responds (especially if naive/untreated before) better to Anti-VEGF than SRF. Small refractory SRF may be left, if the vision is stable (no need to dry it completely). IRF is either Degenerative (smaller & more square shaped & is due to disintegrated RPE & neural elements) or Exudative (larger more active exudation & more oval & responds better to anti-VEGF Tip-331...... Anterior vitrectomy tips after posterior capsular rent (PCR) during Phaco for anterior segment surgeons....... Primary aims are to clear the vitreous from AC (without pulling/traction on vitreous (base) & to avoid enlarging PCR. Use closed chamber technique (keep AC always formed) with 2 side ports. Lower the bottle height. Keep low vacuum & flow rate but highest cutting rate (that machine allows, reduces traction). Infusion cannula tip is kept close to port but away from PCR.
Vitrectomy cutter tip is kept just under the PCR. Tip-332...... Upto 50% of patients of diabetic macular edema (DME) may not respond or become refractory to anti-VEGF treatment (no BCVA or CMT improvement). Cause is supposed to be mitochondrial oxidative damage (apoptosis). Flavoprotein fluorescence (FPF) is the new biomarker test for mitochondrial function, this is checked by Ocumet Beacon device (from Ocusciences, Michigan, USA). Oxidised FPF indicates mitochondrial dysfunction. Thus unlike OCT, it acts as functional test (Retinal metabolic analysis) and not structural. Tip-333..... For detecting metallic RIOFB, always order the CT scan with 1mm (or sub-mm) sections through the globe so as not to miss the foreign body. Tip-334....... On OCT scan, Central retinal/macular thickness (CRT/CMT) measures the mean retinal thickness within 1mm diameter circular field surrounding the fovea, while
Central foveal thickness (CFT) or Centre point thickness measures the retinal thickness at the intersection of 6 radial scan lines. Tip-335...... Patients with Cone dystrophy are highly photosensitive & they benefit from tinted glasses especially orange or red coloured, because rods' sensitivity is less to orange and red lights. Photosensitivity is actually due to poor visual acuity in bright lights and not real intolerance to light Tip-336..... Drusen are the hallmark of AMD, but presence of drusen in old people doesn't always mean AMD, as hard drusen (see Tip62) (especially if scanty, scattered or nonconfluent) can occur in aging retina without developing any significant AMD changes like soft drusen and CNVM throughout the life. Aging retina and AMD is a spectrum and no definite demarcation line exists between the two. Tip-337....... Intraoperative OCT (iOCT) for real time scans during vitreo-macular interface surgeries is now being increasingly used, as
it provides detailed intraoperative anatomical views which are not possible with microscope (difficult visualisation of transparent structures without dye). It provides real time, high resolution visualisation of all the surgical maneuvers e.g. whether ERM removal is complete, any full thickness break introduced during the surgery, etc. Tip-338..... 'Double-layer sign' on SD-OCT scan was first described in Polypoidal choroidal vasculopathy (PCV), but has now been shown in AMD, chronic CSCR, high myopia and other Pachychoroid diseases also. There is irregular and shallow PED with two separate hyper-reflective bands on OCT: upper of RPE & lower one is of Bruch's i.e. separation of RPE & Bruch's. Tip-339...... PCR testing (detects DNA) in general is considered more specific than serological testing (e.g. ELISA for IgG/M). Hence in Ocular Toxoplasmosis, PCR testing in aqueous or vitreous samples is more specific and reliable than ELISA.
Tip-340..... Hyper-reflective dots (HRD)/Spots/Foci are an SD-OCT finding in many retinal diseases (DME, AMD, Vascular occlusions, CSCR, Commotio retinae, etc.). It could be of inflammatory or non-inflammatory (microglial cells having phagocytosed outer segments of photoreceptors) origin. Unlike hard exudates, it can occur in any of the retinal layers & cause no shadowing. HRDs are generally considered an ominous sign & the bad OCT biomarker. (Also see Tips- 78 & 207). Tip-341.... There is no definite treatment known for serous or drusenoid pigment epithelial detachments (PEDs). For Hemorrhagic or fibrovascular PEDs, Anti-VEGF injection, PDT or retinal laser (if extrafoveal) is required. Serous PEDs in CSC resolve in majority or may leave behind the pigment mottling. Extrafoveal PEDs don't affect the vision unlike subfoveal ones. Drusenoid PEDs have the best prognosis, while hemorrhagic or fibrovascular PEDs have the worst. Large PEDs on anti-VEGF injection may develop RPE Rip (see Tip-200).
Tip-342...... Ocriplasmin (Jetrea) by ThromboGenics/Oxurion Inc.: FDA approved (2012) for Intravitreal injection for symptomatic vitreo-macular adhesion (VMA) (seeTip-85). Is modified human Plasmin enzyme. Cost ~4000 USD (marketed by Novartis). Production discontinued since 2020. Was available as 0.5mg/2ml injection. Diluted to 0.4ml & finally 0.125 mg is injected as one time injection. Resolves VMA in ~25%. Tip-343...... Broadly among the congenital retinal dystrophies, in general, Retinitis pigmentosa, Leber congenital amaurosis (LCA) & Cone-rod dystrophies are progressive; while CSNB & Monochromatism are stationary. Tip-344...... None of the Ultra-wide field fundus cameras (including Optos Daytona) can take ora to ora fundus photo in one click. Optos provides the largest field of view (FOV) of 200° (80% of fundus in one field). Zeiss Claris/130° FOV, Spectralis/102° FOV & Mirante/160° FOV (Nidek) provide
the true colour perception & higher image resolution. Spectralis (both contact & non-contact options are available for USF imaging) makes closer contact with patient even with non-contact option. Retcam (CMS, USA) also uses contact lens, hence cumbersome. Tip-345..... Vitamin-A supplements should be avoided in ABCA4 associated retinopathies (e.g. Stargardt's disease). ABCA4 gene (located on chromosome -1) is responsible for the production of protein that cleans up the substance which damages the photoreceptors (actually by A2E , the bisretinoid chemical that gets excessively produced). Approximately 50% of all autosomal recessive cases of Cone-rod dystrophies are related to ABCA4 gene mutations (making it defective). Stargardt's patients should also be asked to quit smoking. Tip-346…... Patients of ARMD, DR, RP or even Optic neuritis, Ocular migraine & Vertebro-basilar ischemia can also complain of flashes of light or photopsiae besides classically mentioned for PVD & RD. These are the
Phosphenes (visual hallucinations induced without any external light). Patients describe it as flashes, moving stars, different shapes of colours which are floating or shimmering or zigzagging. Phosphenes may sometimes occur even in normal eyes & can be induced by rubbing, pressing or moving the eyeballs. Phosphenes occur due to direct or indirect stimulation of photoreceptors or neurons in LGB or visual cortex. Tip-347...... Intravitreal injection of Pegcetacoplan (Syfovre by Apellis Co.) has been approved by FDA (in Feb'23) for Geographic atrophy (advanced form of dry AMD). There was no approved treatment for Geographic atrophy so far. Pegcetacoplan (15 mg in 0.1 ml injection) is a localised complement C3 inhibitor of immune system. May be commercially available in Mar'23. Tip-348...... In future, measuring choroidal thickness (by SS-OCT) in myopia might be used as predictive biomarker for eyeball elongation and thus myopia progression. Choroidal thickness and axial length are probably inversely related. Decreased choroidal blood
flow causes choroidal thinning & scleral architectural changes with elongation of eyeball and induction of progressive and pathological myopia. Tip-349...... Choroidal circulation (supports RPE & outer retinal metabolism) impairment with changes in choroidal thickness is implicated in the pathogenesis of hosts of retinal disorders: ARMD, PCV, CSR, Myopic chorioretinal atrophy, etc. EDI-OCT & Swept source OCT are used to measure choroidal thickness. SS-OCT instrument acquires a choroidal thickness map using a fully automated choroidal segmentation algorithm with good reliability and reproducibility. No standard international protocol is available for measuring choroidal thickness by OCT. Tip-350..... Definition of Wide field imaging (50-100°) for all fundus imaging modalities (fundus photo, FFA, FAF, OCT, OCTA) is that it should capture all four retinal quadrants including posterior edge of vortex ampulla, while Ultra wide field imaging (UWF) captures beyond anterior edge of vortex ampulla in all 4 quadrants (100-200°).
Machines for UWF OCT (See Tips- 312 & 313) are: -Heidelberg Spectralis HRA-OCT -Silverstone (Optos) -Mirante (Nidek) -Plex Elite 9000 (Zeiss) -Xephilio OCT-S1 (Canon). Tip-351..... Congenital rubella retinopathy (CRR, main manifestation of Congenial rubella syndrome) may mimic Retinitis pigmentosa (RP). However, Rubella virus affects the RPE causing its necrosis and atrophy with both hypo & hyperpigmentation (Salt and pepper retinopathy). Also unlike RP, retinal vessels are normal (not attenuated), visual functions ((VA, CV, VF& ERG) remain normal & Rubella retinopathy affects posterior pole mainly (mid periphery affected first in RP). No treatment is required for CRR except for rare associated macular CNVM. Tip-352...... On OCT scan, CNVM is seen as subretinal or sub-RPE hyper-reflective (whitish) lesion with or without IRF, SRF or/& sub-RPE fluid (PED).
Tip-353...... Unlike leakage of dye on FFA in AMD, leak in myopic CNVM is small and less exudative and hence is easier to miss. Moreover, CNVM is type-2 (subretinal) in myopia unlike AMD (type -1 i.e sub-RPE) & affects central vision more, also it responds better to Anti-VEGFs. ICG detects this leak better than FFA Tip-354...... Choroidal thickness (CT) decreases in AMD, aging retina & high myopia, while CT increases in Pachychoroid diseases (see Tip-29) like CSR, PCV, etc. CT is maximum subfoveally and decreases towards periphery especially nasally. CT is highly variable & even varies during the day, because of its high vascularity unlike the retina. Tip-355...... Brands with close to AREDS2 formulation (Daily dose: Vit-C 500mg, VitE/Tocopherol 400 IU, Zn 80mg, Cu 2mg, Lutein 10mg & Zeaxanthin 2mg). Dose for all of them 1 Tab/Cap BD -Tab Luzired (Lupin), Tab ARETS (Microlab) & Tab Vcolux (HIS Eyeness)- have Exact AREDS-2 formula
-Cap Omega red (Alembic)- Has extra omega-3 fatty acid. -Tab Eyesurge (IPCA)- No vitamins E & C, but has Bilberry extract, Resveratol, Astaxanthin & Tocotrienol. -Cap I Gem-6 (Optho lifesciences) has extra Glutamic acid & elemental Zn of 12.5 mg only. -Tab PreserVision AREDS-2 (B&L)- Original AREDS-2 formula (available on Amazon). Tip-356..... In diabetic retinopathy, chances of developing neovascularisation (NV) almost directly correlates with the extent of capillary non-perfusion (CNP) areas. On conventional FFA, CNP areas were mostly described in mid-periphery; while NV occurs more often in posterior pole. But now with UWF-FFA, one can find more peripheral CNP areas than in mid-periphery causing NV. Tip-357...... Per unit area wise, retinal tissue has the highest oxygen demand, even more than that of brain. As it can't deposit oxygen within itself, it needs continuous and efficient blood supply for its nutrition.
CNP areas on FFA are seen as areas of hypofluorescence, but unlike blocked fluorescence, these have capillaries outlining it. Tip-358...... Important RCTs/Studies in DME (Diabetic macular edema): -ETDRS (1979-85)- defined CSME -READ-2- Ranibizumab (R) vs with/without laser -RIDE & RISE- Safety and efficacy of R. -RESOLVE -RESTORE- R. vs laser -DA VINCI- role of VEGF-Trap/Eylea (E) in DME -VISTA- E. in DME -MEAD- Dexa implant in DME -Protocol-T of DRCR.net- compared I-Vit R., E. & Bevacizumab in DME (see Tip297). Tip-359...... 95% of NVG cases are due to retinal ischemia in PDR, CRVO & Carotid artery occlusive disease/CAOD (causes Ocular ischemic syndrome). B/L NVG is mostly due to PDR. In CRVO, NVG can develop between 2 weeks to 2 years (90 days glaucoma, majority within 6 months).
NVG in CAOD can have normal or low IOP (ciliary hypoperfusion). NVI or NVA usually occurs before IOP rise, hence important to detect early. Mx of NVG- PRP with/without I-Vit AntiVEGF is the mainstay of therapy. Antiglaucoma drugs, topical steroids and atropine ointment. If all fails, surgery. Trab. alone mostly fails (try with MMC). Valved shunts better. Cyclodestruction (photocoagulation or cryo), if poor visual potential. Tip-360..... On OCT scan, characteristically in Choroidal granuloma (e.g. Tubercular) unlike non-inflammatory choroidal lesions (e.g. Melanoma), RPE-choriocapillaris layer makes close contact with overlying neurosensory retina overlying the granuloma ('Contact sign') because of inflammatory adhesions. There is surrounding SRF & infiltration in deeper retina. Tip-361..... Normal iris vessels are radial, while vessels of NVI are tortuous and curly. Always check for NVI before dilating pupils in any suspected case. Ectropion uveae may give a clue to rubeosis. Only NVA (angle, NV crossing over scleral spur or trabecular
meshwork) may be there without any NVI in CRVO. Both can commonly be detected before IOP rise/NVG. Sometimes, NVI/NVA may start in ischemic CRVO in 2-3 weeks. Tip-362..... With I-Vit Anti-VEGF injection in AMD, DME, BRVO, etc., response is generally expected within about 2 weeks, although it may start early in a few patients. Normally, OCT should be repeated at 2 weeks to see for reduction in macular thickening. Tip-363..... Choroidal sclerosis (CS)is an obsolete term used to describe the fundus appearance with prominent large whitish (without blood) choroidal vessels. Now the term is used as synonym for Choroideremia. Most common cause of CS described was retinal senescence, i.e. senile atrophy of outer retina, RPE, choriocapillaris and medium sized choroidal vessels. There is no choroidal thickening (sclerosis) in senescence or myopia, rather thinning occurs.
Tip-364...... There is faster washout of Intravitreal AntiVEGF injection in vitrectomised patients as compared to non-vitrectomised eyes, hence needing repeat injection early. Tip-365..... Ocular ischemic syndrome unlike Diabetic retinopathy is/has: -Seen in older patients -Mostly unilateral or grossly asymmetrical -Hemorrhages are larger, mid-peripheral or peripheral. -Retinal arterial narrowing -No hard exudates. -On FFA, delayed choroidal and retinal filling. -On ERG, both a & b waves are affected (predominantly b wave in DR). Tip-366...... Hand-held SD-OCT devices are now commercially available e.g. Envisu/Leica, iVue/Optovue, Spectralis Flex/Heidelberg. These are more difficult to operate & have motion artefacts. Home based (self-check OCT devices) OCTs are now being developed which have low cost, less bulky & easy to use e.g. MIMO OCT.
High risk AMD patients can self monitor with it. Tip-367...... When to suspect MacTel clinically: 1. Greying or decreased transparency of retina in parafoveal area bilaterally in middle aged patient (usually MacTel type2). 2. SD-OCT is characteristic with intraretinal cysts without any increase in retinal thickness. 3. FFA shows juxtafoveal leakage in temporal macula. Primarily, deep capillary plexus is affected & not the superficial one as seen on OCTA. Primary treatment is observation. I-Vit AntiVEGF must be avoided, unless neovascularisation has occurred. Tip-368.... Diabetic retinopathy never causes subretinal hemorrhage, as it is the inner retinal disorder. Tip-369..... Tilted (oblique) disc syndrome, commonly associated with high myopia and astigmatism, can also sometimes cause serous macular detachment, mimicking CSR.
Tip-370..... In Cilio-choroidal detachment, ora becomes easily visible on indirect Ophthalmoscopy even without indentation. It is seen as solid looking, brownish-orange smooth elevation. Suprachoroidal fluid is always greater anteriorly as adhesions between uvea and sclera are loose anteriorly as compared to posteriorly. Tip-371...... Best dystrophy (Vitelliform) unlike Cone dystrophy usually starts very early in childhood & is primarily a disease of RPE (accumulation of lipofuscin like material) & has better prognosis with asymmetric vision loss with at least one eye maintaining better vision. While Cone dystrophy starts later & is primarily the cone disease causing symmetric and more severe visual loss. Tip-372..... Intact choriocapillaris (indicated by choroidal flush) on FFA in Retinitis pigmentosa indicates better prognosis, while poor flush with only late staining indicates worse prognosis.
Tip-373..... Small, flat, persistent or recurrent NVEs are easily missed on clinical examination in heavily lasered diabetic retina, for which FFA is essential. Tip-374...... Foveal hypoplasia (e.g. in ocular albinism & aniridia) is seen as ill-formed Foveal avascular zone (FAZ) on FFA. It causes poor vision and nystagmus in child Tip-375...... There are no higher chances of reactivation of healed posterior uveitis following cataract extraction, hence there is no need for giving preoperative or postoperative systemic steroids in these patients. Tip-376....... Patients of diabetic retinopathy having large areas of neovascularisation around the macula and disc are more likely to develop tractional RD (TRD) and hence greater likelihood of loss of vision following laser treatment (PRP). Tip-377..... Always think of other causes of vitreous hemorrhage also (e.g. trauma, vascular block, etc.) in a diabetic patient, if diabetic
retinopathy is grossly asymmetrical in two eyes. Tip-378...... Paediatric retinal detachments are much less common than those in adults but are more challenging as they present late, having usually already involved the macula and being frequently bilateral. Moreover functional success is also less due to more likely post-surgical adverse events, refractive error and amblyopia. Rhegmatogenous RD remains the most common type with trauma and myopia being the commoner causes. Tip-379...... Some retina specialists prefer single spot laser over the pattern scan laser (e.g. Pascal) for PRP laser as the former covers the CNP and neovascular areas better providing higher chances of regression. Tip-380...... There is no worsening of disease process of AMD because of cataract surgery. Tip-381...... Choroidal folds (idiopathic or secondary), if chronic are commonly asymptomatic; while
those acquired acutely cause diminution of vision and metamorphopsia. Tip-382..... Among the 3 Flucinolone acetonide eye implants (Iluvein, Retisert & Yutiq), Iluvein Intravitreal implant (0.19mg/190 microgm) is approved for non-responding DME & works for 36 months. Given Intravitreally with applicator having 25G needle. Retisert & Yutiq are for non-infectious posterior uveitis. Tip-383..... High dose anti-VEGFs e.g. Ranibizumab of 1-2 mg (standard dose of 0.5mg) & Eylea of 4-8 mg (standard dose of 2mg) have been tried with better results in some patients of PCV & refractory AMD, etc. by some researchers. Tip-384...... Diabetic patients with more significant changes of DR & DME are more likely to progress and deteriorate following cataract surgery than those having milder or no DR/DME. Hence some surgeons prefer doing cataract surgery earlier in diabetics than in non-diabetics.
Tip-385...... Diabetic macular edema (DME) is considered non-relevant clinically if there are only occasional microcysts around the fovea on OCT which are associated with only minimal thickening. Tip-386...... Some patients initially responding well to anti-VEGFs, become refractory to treatment or keep recurring during treatment, because of tachyphylaxis or tolerance. Switching to another anti-VEGF sometimes helps unless mitochondrial oxidative damage (apoptosis) has occurred (see Tip-332). Tip-387...... Posterior capsular rupture during cataract surgery in a patient with diabetic retinopathy & maculopathy can grossly worsen the DR & DME thereby seriously compromising the visual recovery. Tip-388...... Most retinoblastomas are sporadic (nonfamilial) in nature, majority of which are somatic mutations (~25% only are germline mutations) and are usually unilateral and unifocal and not transmissible to next generation.
Tip-389...... Altitudinal retinopathy can occur at high altitudes (mostly at >2500m height) due to hypoxemia causing multiple superficial retinal hemorrhages and sometimes disc edema. Usually spontaneous full recovery occurs on descent. Oxygen administration helps. Cerebral and pulmonary edema may occur concurrently. Tip-390...... The patent for Lucentis expired in 2015 in India, after which the Razumab (from Intas) was launched. Patent for Eylea expired in June'23, clearing the way for its biosimilars to be launched. Pharma companies make 80% of their revenue while the drug is still on patent. Tip-391..... Advantage of Brolucizumab (Pagenax) is its longer duration (repeat injection at ~12 weeks) of action, although 3 initial monthly loading doses are required. In addition, it is the smallest molecule (26 kDA) among the presently available anti-VEGFs used in ophthalmology. Smaller molecules are thought to penetrate retina better to reach choroid and hence may be more effective.
Greater incidence of intraocular inflammations was its major disadvantage. Tip-392...... Best (Vitelliform) dystrophy & Stargardt's disease (Fundus flavimaculatus) are primarily the RPE disorders secondarily affecting the photoreceptors, while Cone dystrophy is the primary photoreceptor disease, hence causes more severe visual loss. Tip-393...... Most common cause of unilateral vitreous hemorrhage in young patient (<40 years of age) with the other eye being totally normal is the ocular trauma (may be in the remote past & forgotten by the patient). Always look for associated signs like sphincteric tear, traumatic mydriasis, angle recession, etc. Eales' patients usually have some signs of vasculitis in the other eye also. Tip-394....... Interferon (INF)-Alfa2b topical eye drops (1ml of Intalfa/Intas injection diluted with 2 ml of d/w & maintained in cold chain) (often used off-label in Ocular surface squamous neoplasia, etc.) have been tried in refractory post-uveitic macular edema, refractory
pseudophakic CME & DME with some success. INF-alpha has both anti-inflammatory and anti-proliferative properties. Tip-395...... FDA in August'23 has approved the second drug for Geographic atrophy form of ARMD. 'Avacincaptad pegol' (Izervay) by Iveric Bio/Astellas Pharma is an Intravitreal solution & is Complement C5 inhibitor. It will be commercially available in a month time in USA. First drug approved for Geographic atrophy in Feb'23 was Pegcetacoplan (Syfovre), see Tip-347. Tip-396..... 3 major adverse effects of laser treatment unlike with Intravitreal anti-VEGF in ROP include: 1. Restricted fields, making it tubular. 2. Definite higher incidence of myopia. 3. Macular hypoperfusion. Tip-397...... Tractional retinal detachment e.g. in proliferative diabetic retinopathy unlike Rhegmatogenous retinal detachment has an elevated concave appearance, no significant
mobility & there are striae that appear radiating out from the site of traction. Tip-398.... On Ophthalmoscopy or FFA, choroidal vessels unlike retinal vessels appear broader, less sharply defined, flat and ribbon like, show no light reflex, don't branch dendritically or anastomose & instead appear to form dense network. Tip-399.... Intravitreal injection of any anti-VEGF should preferably be avoided for 1 year or for at least 3 months after an acute AMI or CVA (stroke) as there may be increased susceptibility to systemic adverse events including mortality at this stage (although not supported by all studies). Tip-400..... Always think of Polypoidal choroidal vasculopathy (PCV) if you see significant fundus findings like subretinal hge, fluid and exudation in posterior pole especially if occuring unilaterally in younger patient (50- 60 years, i.e. younger than in AMD) but find no significant cause on fundus examination (e.g. drusen, RPE changes, telangiectasia, aneurysm, etc.) in diseased or fellow eye. Order the ICGA or OCTA to rule it out.
Tip-401...... Lutein and Zeaxanthin are naturally occurring macular carotenoids (mainly present in IPL, OPL & Muller cells). They are antioxidants and blue filtering that can prevent the macular damage and AMD. These can't be synthesized by human body and hence need to be consumed in food. Good sources of these include green leafy vegetables (spinach, broccoli, lettuce, etc.), fruits (grapes, kiwi, orange), egg-yolk, capsicum (bell-pepper), pistachio, etc. Tip-402...... The strongest association of HLA and eye disease is in Birdshot chorioretinopathy/BSC (chronic, B/L, autoimmune posterior uveitis of middle aged caucasian females). Almost 90% of patients of BSC have HLA-A29 positivity, hence its diagnostic importance, while association of HLA B27 with uveitis is not so strong. Tip-403...... Prematurely born neonates have definite higher incidence of myopia (Myopia of prematurity), which becomes more likely if infant develops ROP, and incidence is still higher if they are treated by laser. Exact mechanism is unknown, however anterior
segment development is abnormal and axial length increase is not the cause. Tip-404...... Anti-VEGF in chronic CSC should be used only if CNV (present in only ~5% of cases of chronic CSC) has been shown on ICGA or OCTA. Greater choroidal thickness & larger pachyvessels (outer choroidal/ Haller's) make prognosis poorer in chronic CSC. Tip-405...... PDR is a medical emergency and must be lasered early, while DME is NOT so and one should reasonably control all the metabolic and systemic parameters before undertaking any local treatment (antiVEGFs) to provide the optimal benefit. Tip-406...... In Gene therapy for AMD (both dry and wet), gene is injected into the eye to stimulate its own production of anti-VEGF. It has the potential for single life-time injection. Envelope of viral vector is used for carrying encoded genetic sequence into the target cell (RPE & retinal cells) forcing it to produce anti-VEGF chemical. Injection is given either under the retina or choroid.
Suprachoroidal approach is easier and preferred. Phase-3 trials are already on. Tip-407...... Presently the treatment of choice for PCV is combotherapy of PDT + Intravitreal Aflibercept. However, PDT not being available now, Aflibercept monotherapy is now acceptable and is being commonly used. Tip-408...... Wet AMD patients under active treatment or on follow up, must be asked to check with Amsler grid daily (each eye separately) to detect the deterioration early. Tip-409...... In PCV unlike nAMD, RPE remains relatively intact, VEGF release is less and prognosis is more favorable. On OCT in PCV unlike nAMD, one finds: 1. Notching or peaking in PED (due to polyps projecting into PED). 2. Double layer sign (see Tip-338). Tip-410...... AREDS-2 formula drugs (see Tip-355) have no role in dry AMD with hard drusen, geographic and non-geographic atrophy. Give them for intermediate AMD (medium
drusen of 63-125 micron size with focal hyperpigmentation or 1 or more soft drusen). To estimate the size of drusen, compare it with CRV entering the optic nerve head which is ~125 micron. Tip-411...... Conbercept is an Intravitreal anti-VEGF drug akin to Aflibercept and is also the recombinant fusion protein neutralizing VEGF-A,B,C and PGF. It is already being extensively used in China for nAMD, etc. since 2014. Developed by the Chinese company, it is not US-FDA approved. Tip-412..... Intravitreal anti-VEGF injections should be avoided or are not indicated or contraindicated in: 1. Fibrovascular proliferation with macular threatening, unless early VR surgery planned. 2. Active ocular or periocular infection or inflammation. 3. Pregnancy & lactation 4. Serous PED 5. Ischemic diabetic maculopathy 6. Dry AMD (No CNV) Contd. in Tip-413
Tip-413..... Contd. from Tip-412. Intravitreal anti-VEGF injections should be avoided or are not indicated or contraindicated in: 7. Geographic or non-geographic atrophy of AMD. 8. Allergy to anti-VEGF 9. Chronic CSR without CNV. 10. Retinitis pigmentosa 11. MI or CVA in last 3 months. 12. Patient who refuses to undertake or can't undertake repeated injections (especially in AMD & DME). 13. Full thickness macular hole and Rhegmatogenous RD. Tip-414....... In USA, some retina specialists are giving bilateral Intravitreal anti-VEGF injections (like bilateral simultaneous cataract surgery in selected patients) in DME & nAMD with separate set of instruments, syringes, etc. Tip-415...... 5 relatively commoner side effects of PRP laser, about which patient must be warned, include: Decrease in visual acuity Constricted visual fields Altered colour vision
Impaired dark adaptation Decreased contrast sensitivity. Tip-416....... Presently 3 important indications of ICG angiography include: PCV Chronic CSR Choroidal hemangioma Tip-417....... Earlier ICG angiography used to be an important tool to know whether the CNV in nAMD is Classic or Occult. However after the advent of anti-VEGFs, it has become irrelevant as the treatment for both remains the same. However, if there is even is a little suspicion of PCV, getting an ICGA or OCTA becomes important. Tip-418...... Advantages of FFA over OCTA include: Dynamic study- identifies leaks (tells whether neovascularisation is still active or regressed) & CNP areas Long experience Cheaper Wide field (even 200° with Optos) Good images possible even in non-fixating patient.
Tip-419...... Disadvantages of FFA over OCTA include: Only superficial retinal vasculature studied Considered invasive (injected dye can have side effects) & contraindicated in some patients. Less resolution Only 2-D picture Tip-420....... Uveitis that need immunomodulators as first line treatment include: 1. Behcet's disease 2. VKH syndrome 3. Sympathetic ophthalmia Tip-421........ In pathological myopes, both Lacquer cracks (breaks in Bruch's) and patchy chorioretinal atrophy (unlikely with diffuse chorioretinal atrophy) in macula can lead to development of CNVM. Tip-422...... Features of Masquerading uveitis associated with Vitreoretinal lymphoma (Primary intraocular lymphoma/PIOL; Also see Tip104) include: 1. Patient has vitritis but No CME and good visual acuity.
2. Outer retina and RPE giving leopard skin appearance (see Tip-289) on fundoscopy. 3. PIOL doesn't extend into choroid with intact Bruch's on OCT, hence choroidal biopsy is of no use. 4. Diagnostic vitrectomy is compulsory to identify abnormal cells. 5. Patient improves on steroids, but deteriorates immediately on tapering. Tip-423...... Eye is an ideal target for Gene therapy because of: 1. Immune-previliged status - blood-eye barriers (compartmentalised). 2. Exclusive ophthalmic monogenic disorders' total cure is possible (e.g. R.P, CSNB, LCA, Rod-cone disease, etc.). 3. Easy accessibility for treatment (by I-Vit injection or Vitrectomy). 4. Easy clinical evaluation (optical transparency) by fundus examination, OCT, ERG, etc. Most successful is RPE65 gene replacement in LCA2. Tip-424...... Full thickness necrotizing retinitis is almost always due to infectious etiology.
Tip-425...... In myopic CNVM, unlike AMD & DME where repeated anti-VEGF injections are always required, one needs to give the single anti-VEGF injection followed by injection on PRN basis. Even after CNVM regression following antiVEGF injection, vision can deteriorate due to enlarging atrophy in previous CNVM region. Tip-426.... IOP rise is common after PRP laser with peak occuring around 2 hours post-laser. Fluid exudation from retina and choroid is the likely cause. Higher laser energy and larger treated retinal area is an important risk factor. Tip-427...... Active CNVM on OCT is subretinal/subRPE hyper-reflective lesion which is less well defined (amorphous) with fuzzy or irregular edges with intra or subretinal fluid. Tip-428..... Macular pseudohole is a clinical diagnosis on fundus examination where ERM in fovea causes retinal contraction that gives the appearance of a hole. In Lamellar macular hole (diagnosed on OCT), there is steep and
irregular foveal contour with loss of inner retinal tissue unlike pseudohole. Secondary Lamellar macular hole can form from CME and DME. These cases don't benefit from vitrectomy. Most lamellar macular holes don't require treatment unless vision is deteriorating on follow up. Tip-429...... Subretinal blood commonly indicates CNVM, but not always so e.g. in lacquer cracks, traumatic choroidal rupture, macroaneurysm, etc. Tip-430...... High myopia doesn't always mean pathological myopia which has tessellated fundus, peripapillary atrophy, tilted discs, diffuse or patchy chorioretinal atrophy, lacquer cracks, posterior staphyloma and myopic maculopathy. Tip-431...... IOP rise following Intravitreal anti-VEGF injection (in approximately 5%) is most commonly seen with Bevacizumab. Commoner in pre-existing glaucoma patients. Primarily due to outflow compromise (exact cause?). Incidence
increases with increasing number of injections. Tip-432....... Likely side effects/ complications of Intravitreal anti-VEGF injections: 1. Infections 2. RPE rip (see Tip-200) Repeated injections may cause - 3. Persistent rise of IOP (see Tip-431). 4. Aggravation of geographic atrophy changes. 5. Scleral structural changes -thinning. Vary the site of injections. Tip-433..... Many studies have shown that topical antibiotics prescribed before or after Intravitreal injections have no role in preventing endophthalmitis. Tip-434...... Laser pointers usually have <5 milliwatts power (class llla of older classification & class 3R in newer classification) can also be sometimes hazardous to the eyes causing Laser induced retinopathy with macular damage (Ellipsoid zone & RPE are primarily affected). In USA only those laser pointers with <5 milliwatts are allowed to be sold commercially, although many of those sold
are wrongly labelled in terms of output. Some recovery may occur and steroids are empirically tried. Tip-435..... Think of ARRON (Autoimmune related retinopathy and optic neuropathy) in cases where unexplained retinopathy with optic neuropathy has occurred (diagnosis of exclusion). Visual loss is bilateral and without any specific fundus findings. Autoantibodies are detectable in the serum. Tip-436..... Intravitreal drugs (Pegcetacoplan and Avacincaptad) are now FDA approved for slowing down the progress of Geographic atrophy form of ARMD. The growth slowdown is very limited and the cost burden is huge. Tip-437....... Bacillary layer detachment (BALAD) is a disease non-specific OCT finding where intraretinal fluid (IRF) accumulates and split occurs within the inner segment of photoreceptors (between Ellipsoid and Myoid zones) i.e. outer to ELM. Cause is sudden and rapid IRF (not the SRF) accumulation.