Seminars in ophthalmology
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Optic disc drusen are congenital and developmental anomalies of the optic nerve head seen commonly in clinical practice, often as an incidental ophthalmologic finding during routine exams. Optic disc drusen are a form of calcific degeneration in some of the axons of the optic nerve. Visual acuity is often not affected but the visual fields of these patients can be abnormal and deteriorate over time. ⋯ The diagnosis can be made with clinical findings combined with B scan ultrasound and computed tomography. In addition, newer modalities using optic nerve head tomography are proving to be very useful. Since children as well as adults are affected, it is important to consider optic nerve head drusen in the differential diagnosis of papilledema or optic nerve swelling.
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Seminars in ophthalmology · Dec 2003
Case ReportsTopical phenylephrine may result in worsening of visual loss when used to dilate pupils in patients with vaso-occlusive disease of the optic nerve.
Four patients (age range 54-82, 1F 3M) diagnosed with non-arteritic ischemic optic neuropathy experienced acute worsening of visual function after instillation of phenylephrine for dilated funduscopic examination. They experienced decreased visual function immediately or shortly after administration of topical mydriatic drops given in preparation for funduscopy. In all cases one drop each of 2.5% phenylephrine and 0.5-1% tropicamide was used. ⋯ Vasoconstriction of the watershed posterior ciliary capillary beds may result in further precipitating infarction of already compromised circulatory territories in edematous optic nerves. Because phenylephrine is a known vasoconstrictor in vivo and in vitro, it is more likely to cause deleterious vasoconstriction and an acute decline in visual function in patients with acute ischemic optic neuropathy than tropicamide. The routine practice of using phenylephrine to prepare patients for funduscopic assessment should be re-examined, particularly in patients with ischemic optic neuropathy.