OPHTHALMOBYTES

𝗦𝘁𝗮𝗿𝗴𝗮𝗿𝗱𝘁’𝘀 𝗗𝗶𝘀𝗲𝗮𝘀𝗲⁣ ⁣ ● Most common macular dystrophy⁣ ● Presents within first two decades but central vision loss may not occur until later in life⁣ ● AR- Mutation in ABCA4 gene on chromosome 1p21-22⁣ ● AD Stargardt disease (STGD3) is rarer - ELOVL4 gene⁣ ⁣ 𝘚𝘺𝘮𝘱𝘵𝘰𝘮𝘴:⁣ ● B/L central visual loss, photophobia, colour vision abnormalities, central scotomas, slow dark adaptation⁣ ● Visual deterioration progresses rapidly.⁣ ⁣ 𝘍𝘶𝘯𝘥𝘶𝘴: ⁣ ● Affects the

𝐂𝐡𝐨𝐫𝐨𝐢𝐝𝐞𝐫𝐞𝐦𝐢𝐚⁣ ⁣ ● X linked recessive chorioretinal dystrophy⁣ ● Diffuse, progressive degeneration of the RPE, photoreceptors and choriocapillaries⁣ ● Mutation in CHM gene codes for REP-1 ( Rab escort protein) , Xq21⁣ ⁣ 𝐏𝐚𝐭𝐡𝐨𝐠𝐞𝐧𝐞𝐬𝐢𝐬⁣ ⁣ ● Primarily degeneration of RPE cells or choroid or both with secondary degeneration of rods and then cones⁣ ⁣ 𝐂𝐥𝐢𝐧𝐢𝐜𝐚𝐥 𝐅𝐞𝐚𝐭𝐮𝐫𝐞𝐬⁣ ⁣ ● Symptomatic during 1st decade of life⁣ ● Nyctalopia/night blindness⁣

𝐋𝐨𝐬𝐭 𝐟𝐨𝐯𝐞𝐚!⁣ ⁣ 𝘖𝘤𝘶𝘭𝘰𝘤𝘶𝘵𝘢𝘯𝘦𝘰𝘶𝘴/ 𝘖𝘤𝘶𝘭𝘢𝘳 𝘈𝘭𝘣𝘪𝘯𝘪𝘴𝘮⁣ ⁣ Albinism is a congenital disorder causing reduced pigmentation due to complete or partial absence of melanin pigment affecting the skin, hair and eye.⁣ ⁣ Absence or defect of tyrosinase which is involved in production of melanin.⁣ ⁣ 𝘛𝘸𝘰 𝘵𝘺𝘱𝘦𝘴:⁣ ⁣ 𝐎𝐜𝐮𝐥𝐨𝐜𝐮𝐭𝐚𝐧𝐞𝐨𝐮𝐬 𝐚𝐥𝐛𝐢𝐧𝐢𝐬𝐦⁣ ● Involves the eye, skin and hair⁣ ● Autosomal recessive⁣ ● Many types - OCA Type 2 is the

𝘓𝘢𝘵𝘵𝘪𝘤𝘦 𝘋𝘦𝘨𝘦𝘯𝘦𝘳𝘢𝘵𝘪𝘰𝘯⁣⁣ ⁣⁣ ● Peripheral retinal degeneration with spindle-shaped areas of retinal thinning, most common degeneration to cause retinal detachment⁣⁣ ⁣⁣ ● 8-10% incidence⁣⁣ ⁣⁣ ● Present in 20-30% of Rhegmatogenous RD⁣⁣ ⁣⁣ ● Symmetrical and bilateral, most common superiorly⁣⁣ ⁣⁣ 𝐀𝐩𝐩𝐞𝐚𝐫𝐚𝐧𝐜𝐞:⁣⁣ ⁣⁣ ● Elongated lesions with long axis parallel to the ora serrata, located in the peripheral retina, usually hyperpigmented and mottled looking⁣⁣

𝘞𝘩𝘪𝘵𝘦 𝘞𝘪𝘵𝘩𝘰𝘶𝘵 𝘗𝘳𝘦𝘴𝘴𝘶𝘳𝘦⁣ ⁣ Incidence increases with age and increased axial length ⁣ ⁣ 𝐀𝐩𝐩𝐞𝐚𝐫𝐚𝐧𝐜𝐞:⁣ ● Translucent white- gray appearance of the equator/ peripheral retina seen without scleral depression⁣ ● Bilateral, Maybe circumferential⁣ ● Bounded posteriorly by reddish brown line⁣ ● Sharply demarcated margins⁣ ⁣ ● Misdiagnosed as retinal detachment/retinoschisis⁣ ● Scleral indentation reveals that retina is opposed to underlying RPE⁣ ● May have

𝘖𝘱𝘵𝘪𝘤 𝘋𝘪𝘴𝘤 𝘏𝘦𝘮𝘰𝘳𝘳𝘩𝘢𝘨𝘦𝘴⁣ ⁣ ● Splinter or flame-shaped hemorrhages ● Perpendicular to the optic disc margin⁣ ● Classically, these hemorrhages are located in the prelaminar optic disc, cross the peripapillary zone, and extend into the adjacent superficial retinal nerve fiber layer⁣ ⁣ ● Disc hemorrhages are a risk factor for progression of glaucoma⁣ ● Most common in normal tension glaucoma⁣ ● Associated with notching of the neuroretinal rim or retinal nerve fi

⁣⁣⁣⁣⁣𝘍𝘶𝘭𝘭 𝘵𝘩𝘪𝘤𝘬𝘯𝘦𝘴𝘴 𝘔𝘢𝘤𝘶𝘭𝘢𝘳 𝘏𝘰𝘭𝘦⁣⁣⁣⁣⁣⁣ ● Round retinal break involving all the layers of the retina at the fovea⁣⁣, more common in females⁣⁣⁣⁣⁣⁣ ⁣⁣⁣⁣⁣⁣ 𝘊𝘢𝘶𝘴𝘦𝘴:⁣⁣⁣⁣⁣⁣ ● Idiopathic⁣⁣⁣⁣⁣⁣ ● Pathological Myopia⁣⁣⁣⁣⁣⁣ ● Blunt ocular trauma⁣⁣⁣⁣⁣⁣ ● Ocular inflammation⁣⁣⁣⁣⁣⁣ ● Cystoid macular edema⁣ etc⁣⁣⁣⁣⁣ ⁣⁣⁣⁣⁣⁣ 𝘊𝘭𝘪𝘯𝘪𝘤𝘢𝘭 𝘧𝘦𝘢𝘵𝘶𝘳𝘦𝘴:⁣⁣⁣⁣⁣⁣ Loss of central visual acuity, metamorphosia, micropsia⁣⁣⁣⁣⁣⁣ ⁣⁣⁣⁣⁣⁣ 𝘗𝘢𝘵𝘩𝘰𝘨𝘦𝘯𝘦𝘴𝘪𝘴:⁣⁣⁣⁣⁣

𝘍𝘍𝘈 𝘧𝘪𝘯𝘥𝘪𝘯𝘨𝘴 𝘰𝘧 𝘈𝘤𝘶𝘵𝘦 𝘊𝘚𝘊𝘙⁣ ⁣ 𝐈𝐧𝐤 𝐛𝐥𝐨𝐭/ 𝐄𝐱𝐩𝐚𝐧𝐬𝐢𝐥𝐞 𝐃𝐨𝐭⁣ ⁣ ● 90%⁣ ● Small, focal hyperfluorescence leak from choroid through RPE⁣ ● Early phase of FFA⁣ ● Increases in size and intensity⁣ ● Multiple leakage spots can be present⁣ ⁣ 𝐒𝐦𝐨𝐤𝐞𝐬𝐭𝐚𝐜𝐤⁣ ⁣ ● 10%⁣ ● Central spot of hyperfluorescence⁣ ● Spreads vertically and laterally in a configuration of a plume of smoke/ mushroom⁣ cloud/ umbrella in the late phase⁣ ● Due to convection cur

𝘈𝘤𝘶𝘵𝘦 𝘊𝘦𝘯𝘵𝘳𝘢𝘭 𝘚𝘦𝘳𝘰𝘶𝘴 𝘊𝘩𝘰𝘳𝘪𝘰𝘳𝘦𝘵𝘪𝘯𝘰𝘱𝘢𝘵𝘩𝘺 𝘗𝘢𝘳𝘵 𝟷- 𝘍𝘶𝘯𝘥𝘶𝘴 𝘢𝘯𝘥 𝘖𝘊𝘛 𝘧𝘪𝘯𝘥𝘪𝘯𝘨𝘴⁣ ⁣ ● Serous detachment of the neurosensory retina in the macular area⁣ ⁣ ● Male patients, 20-55 years⁣ ⁣ 𝘙𝘪𝘴𝘬 𝘧𝘢𝘤𝘵𝘰𝘳𝘴:⁣ ⁣ ● Type A personality⁣ ● Stress⁣ ● Hypertension⁣ ● Smoking⁣ ● Autoimmune disorders⁣ ● Organ transplantation patients⁣ ● Pregnancy⁣ ● Medications such as steroids, sildenafil⁣ ⁣ 𝘗𝘢𝘵𝘩𝘰𝘨𝘦𝘯𝘦𝘴𝘪𝘴:⁣ ⁣ 1. Focal an

𝘕𝘦𝘰𝘷𝘢𝘴𝘤𝘶𝘭𝘢𝘳𝘪𝘻𝘢𝘵𝘪𝘰𝘯 𝘰𝘧 𝘵𝘩𝘦 𝘥𝘪𝘴𝘤 (𝘕𝘝𝘋)⁣ ⁣ ● New vessels on or within one disc diameter of the disc⁣ ⁣ ● Occurs due to attempt at vascularising ischemic retina⁣ ⁣ ● The new vessels lack the integrity and bifurcation of normal vessels and are fragile - bleed spontaneously⁣ ⁣ ● Retinal and vitreous hemorrhages attract fibroglial elements → fibrovascular stalks → vitreous contraction → traction on retina → RD⁣ ⁣ ● The neovascularization arises from the

𝘈𝘯𝘨𝘪𝘰𝘪𝘥 𝘚𝘵𝘳𝘦𝘢𝘬𝘴⁣⁣⁣ ⁣⁣⁣ ● Bilateral⁣⁣⁣ ● Irregular linear breaks in the degenerated Bruch’s membrane⁣⁣⁣ ● Radiate from the optic disc in a cruciate pattern from an area of peripapillary pigment alteration⁣⁣⁣ ● Taper as they go away from the disc⁣⁣⁣ ● Pull of extraocular muscles create stress forces against the fixed point of the optic nerve which results in this pattern⁣⁣⁣ ● Colour varies from red to dark brown depending on the colour of fundus and overlying RPE

𝘚𝘰𝘧𝘵 𝘌𝘹𝘶𝘥𝘢𝘵𝘦𝘴/ 𝘊𝘰𝘵𝘵𝘰𝘯 𝘞𝘰𝘰𝘭 𝘚𝘱𝘰𝘵𝘴⁣ ⁣ - Nerve fibre layer infarcts⁣ ⁣ - Occur secondary to local ischemia from pre-capillary retinal arteriole obstruction → obstruction of axoplasmic flow in the nerve fibre layer → swelling of nerve fibres → white fluffy appearance → cotton wool spots ⁣ ⁣ ⁣ 𝐂𝐚𝐮𝐬𝐞𝐬: ⁣ ⁣ - Vascular Diseases : Diabetic Retinopathy, Hypertensive Retinopathy, Vein occlusions, Ocular Ischemic Syndrome, Papilledema, Radiation Retinopat

𝘏𝘢𝘳𝘥 𝘌𝘹𝘶𝘥𝘢𝘵𝘦𝘴⁣ ⁣ ● Due to chronic localised retinal edema, develops between junction of normal and edematous retina⁣ ⁣ ● Occurs due to leakage from microaneurysms and surrounding capillaries⁣ ⁣ ● Deep yellow with sharp well defined margins, usually between the temporal arcades⁣ ⁣ ● They are composed of lipoproteins and lipid filled macrophages⁣ ⁣ ● Deposited within the neurosensory retina - outer plexiform and inner nuclear layers⁣ ⁣ ● Accumulation may occur in a

⁣𝐌𝐢𝐜𝐫𝐨𝐚𝐧𝐞𝐮𝐫𝐲𝐬𝐦𝐬⁣⁣ ⁣⁣ ● Microaneurysms are usually the first ophthalmoscopically detectable sign of diabetic retinopathy⁣⁣ ⁣⁣ ● Hallmark of nonproliferative diabetic retinopathy (NPDR)⁣⁣ ⁣⁣ ● Mild NPDR- Microaneurysms only⁣⁣ ⁣⁣ ● Also seen in - retinal vein occlusions, radiation retinopathy, hypertensive retinopathy⁣⁣ ⁣⁣ 𝐏𝐚𝐭𝐡𝐨𝐥𝐨𝐠𝐲:⁣⁣ ⁣⁣ ● Focal saccular outpouchings of the capillary wall due to pericyte loss⁣⁣ ⁣⁣ ● Arise from deep part of inner retinal c

Cystoid Macular Edema Accumulation of fluid intra-retinally in the outer plexiform layer and inner nuclear layer due to disruption of the normal blood retinal barrier which causes leakage from perifoveal retinal capillaries and accumulation of fluid with the formation of visible cystic spaces Risk Factors Mnemonic ‘DEPRIVENS’ D - Diabetes (Diabetic Macular Edema) E - Epinephrine P - Pars planitis/ Uveitis R - Retinits Pigmentosa and other retinal dystrophies I - Irvine Gass S

Posterior Vitreous Detachment It is a separation of the posterior vitreous cortex from the neurosensory retina - the vitreous collapses anteriorly towards the vitreous base. Initially there is liquefaction and syneresis → rupture in the posterior hyaloid → liquified vitreous flows out → separates the posterior hyaloid from the retina Begins as a partial PVD at the perifoveal region → progresses to optic disc and formation of Weiss ring Vitreous traction at firm sites of adhes

Retinitis Pigmentosa (Typical) It is an inherited retinal dystrophy characterized by diffuse progressive dysfunction of the rod photoreceptors and subsequent degeneration of cone photoreceptors and the retinal pigment epithelium, usually bilateral and symmetrical. Modes of inheritance: Autosomal dominant- best prognosis Autosomal recessive- most common X-Linked Recessive- worst prognosis Signs and Associations: Functional signs: Night blindness/ Nyctalopia - earliest Photopho

Acute Branched Retinal Vein Occlusion Types: Major BRVO: Occlusion of retinal vein that drains one of the quadrants Macular BRVO : Occlusion of a venule within the macula BRVO can also be ischemic/ non-ischemic- ischemic BRVO: Ischemic is >5-DD of non-perfusion on FFA Risk factors: Hypertension, diabetes, hyperlipidemia, glaucoma etc Young patients - High homocysteine, hypercoagulable states, use of oral contraceptive pills etc. What is the most common site and why is it so?

CENTRAL RETINAL VEIN OCCLUSION (ISCHEMIC in the first picture, NON-ISCHEMIC in the second picture) ⁣ ⁣ CRVO occurs due to the occlusion of the central retinal vein at or posterior to the lamina cribrosa. It causes painless unilateral loss of vision. ⁣ ⁣ Pathogenesis : VIRCHOW’S TRIAD : Vessel damage, Stasis and Hypercoagulability. ⁣ ⁣ The central retinal vein and artery share a common adventitial sheath at arteriovenous crossings posterior to the lamina cribrosa.  Atheroscleo

Horseshoe tears are full thickness breaks in the neurosensory retina that occur due to vitreous traction during posterior vitreous detachment and can lead to rhegmatogenous retinal detachment.⁣ ⁣ They present as a flap of retinal tissue with a detached apex which always points to the posterior pole and a base attached to the retina.⁣ ⁣ When there is vitreous traction and a subsequent retinal tear, the tear is attached to the vitreous as it continues to detach. The vitreous de