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Optic Disc Pit⁣






● Congenital defects arising from failure of fetal fissure closure in embryogenesis⁣

● Mostly unilateral. 10-15% bilateral⁣

Pathophysiology:⁣

● Occur due to incomplete closure of the optic fissure resulting in a micro-communication between the subarachnoid space and the pit.⁣

● Communication of optic pits and Cerebral Spinal Fluid (CSF) is controversial. Beta-2 Transferrin levels (found in CSF) of submacular fluid associated with optic pits has been variable.⁣

● Histologically, there is herniation of a dysplastic retina into the subarachnoid space through a defect in the lamina cribrosa at the pit.⁣

Symptoms:⁣

● Usually asymptomatic.⁣

● Patients may complain of metamorphopsia, micropsia, blurred or decreased vision, or a⁣

blind spot if the optic pit is associated with a serous detachment. ⁣

Signs:⁣

● Usually found inferotemporally within the nerve, 1⁄3 are central⁣

● Round or oval depression that differs in colour from the surrounding disc⁣

(grey, yellow or black)⁣

● Colour variation depends on the amount and location of glial tissue in the pit⁣

● Size can vary from 0.1-0.7 disc diameters and depth from 0.3-0.5 diopters⁣

● Associated macular edema, serous macular detachment; schisis or pigmentary changes in⁣

the macula⁣

● Shallow serous macular detachments can be seen in upto 3⁄4 eyes with inferotemporal pits⁣

Investigations:⁣

● OCT: to determine if trace amounts of subretinal fluid is seen, can show schisis-like separation between inner and outer retina.⁣

● Visual fields – Enlarged blind spot, ​arcuate scotomas .⁣

● Amsler grid can be used to monitor the onset of macular involvement of an optic pit with serous detachment.⁣

Management:⁣

● No medical therapy indicated unless it is associated with optic disc maculopathy⁣

More on optic disc maculopathy in the next ⁣

post!⁣

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𝘐𝘳𝘪𝘴 𝘢𝘵𝘳𝘰𝘱𝘩𝘺⁣







⁣Specific conditions:⁣ ⁣ Age related⁣ ● Atrophy of both iris stroma and pigment epithelial layer occurs as a natural aging process⁣ ● Bilateral, symmetric iris stromal atrophy.⁣ ● Normal pupillary contour with increased prominence of the pigment epithelium and⁣ the pupillary sphincter- tan rings⁣ ⁣ Viral Uveitis⁣ ● Chronic inflammation can lead to characteristic iris stromal atrophy⁣ ● VZV generally produces sector iris atrophy due to a vascular⁣ occlusive vasculitis, whereas HSV usually produces patchy iris atrophy⁣ ⁣ Essential iris atrophy⁣ ● ICE syndrome, unilateral⁣ ● Primary defect is believed to be a cellular membrane secreted by the abnormal endothelial cells which covers the iris and the drainage angle of the eye- contraction leads to pupillary changes and formation of PAS - angle closure glaucoma⁣ ● Displaced or distorted pupil, patchy areas of iris atrophy and holes in iris.⁣ ⁣ Trauma⁣ Post cataract surgery due to trauma to iris can lead to iris atrophy after many years.⁣ ⁣ Pigment Dispersion Syndrome⁣ ● Pigment granules settle on iris surface⁣ ● Posterior bowing of mid peripheral iris⁣ ● Classic mid peripheral,radial slit like transillumination defects in iris best⁣ seen on retroillumination.⁣ ⁣ PXF syndrome⁣ ● Particulate pigment deposition on sphincter and peripheral iris⁣ ● Moth-eaten transillumination defects occur at the sphincter⁣ ⁣ Post acute congestive glaucoma⁣ ● Partial/total absence of pupillary ruff⁣ ● Sphincter atrophy⁣ ● Whorling of the iris radial pattern⁣ ● Sectoral iris atrophy⁣ ⁣ Fuch’s Uveitis⁣ ● Diffuse atrophy of stroma and posterior pigment epithelium of iris.⁣ ● Determines the quality of heterochromia iridis.⁣ ⁣ Albinism⁣ ● Tyrosinase-negative: Lack of melanin⁣ ● Iris is diaphanous and translucent giving rise to a ‘pink-eyed appearance’⁣ ● Tyrosinase-positive: synthesise variable amounts of melanin.⁣ ● Iris may be blue or dark-brown, variable translucency⁣ ⁣ Axenfeld Rieger Syndrome⁣ ● Iris strands adherent to the posterior embryotoxon can range from fine threadlike strands to broad bands of iris tissue.⁣ ● Stroma - generalized atrophy with corectopia, ectropion uveae

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