Pediatric Ophthalmology

152 8 Congenital Abnormalities of the Optic Nerve

OPTIC DISC PITS

decades of life. When subretinal fluid is pres ent, visual acuity decreases to 20/40 to 20/60. Signs ● ODPs are usually seen as single, oval-shaped depressions at the optic disc. They are most commonly found at the inferotemporal aspect of the optic disc but may also be found else where, including centrally. Usually, they are gray, white, or yellowish in color ( Fig. 8-3 ). ● The signs associated with ODP maculop athy include intraretinal and subretinal fluid accumulation, and retinal pigment changes. ● Amblyopia in children especially in eyes with serous macular detachment ● Rarely associated with basal encephalocele Differential Diagnosis ● Optic disc anomalies such as choroidal and scleral crescent ● TDS ● Circumpapillary staphyloma ● Hypoplastic disc ● Glaucomatous optic neuropathy ● Central serous retinopathy and subretinal neovascular membranes for serous macular detachment Diagnostic Evaluation ● OCT to evaluate the subretinal fluid—typi cally, OCT may show a schisis-like separation between the inner and outer retina. ● VF—arcuate scotoma is most common. ● Intravenous fluorescein angiography (IVFA) is helpful in the differential diagnosis of serous detachment. ● Amsler grid can be used to monitor the macular involvement. Treatment ● No treatment is required for an isolated optic pit.

● Optic disc pit (ODP) is an oval or round excavation of variable color, depth, and loca tion in the optic disc. ● The temporal optic disc side is the most commonly involved. ● Often unilateral, although bilateral cases have been reported in 15% of the cases. ● Estimated frequency is < 1 in 10,000 people. Etiology ● It is not entirely clear—they are thought to result from an imperfect closure of the supe rior edge of the embryonic fissure. ● Histologically, an ODP is a herniation of the dysplastic retina into a collagen-rich ex cavation that extends into the subarachnoid space through a defect in the lamina cribrosa. ● The pathogenesis of the macular changes is still controversial—the fluid may be vitreous fluid, cerebrospinal fluid, leakage from blood vessels at the base of the pit, or leakage from the choroid. Also, serous macular detachment is caused by direct communication between the optic pit and the subretinal space or from the optic pit and retina. In the latter case, fluid may move into the retina, causing a schisis-like separation of the inner and outer layers, with the neurosensory serous RD oc curring secondary to this schisis. In addition, vitreous traction appears to be an important factor in the pathogenesis of optic pit–related macular detachment. ● ODPs are generally sporadic, although familial occurrence has been reported as a

dominant trait. Symptoms

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● Optic pits are asymptomatic unless there is subretinal fluid: ~50% of the eyes develop se rous macular detachment, especially with large temporal pits, usually in the second or third