Pathophysiology
1) gradual, painless visual loss affecting mostly elderly patients 2) occurs as an exudative (wet) variant and a nonexudative (dry) variant
Signs and Symptoms
Exudative – 1) blurring and distortion of vision 2) occasionally acute vision loss if neovascular vessels bleed Nonexudative – 3) progressive, bilateral central vision loss
Characteristic Test Findings
Ophthalmoscopy – 1) best for detecting nonexudative variant 2) shows extracellular yellow granular deposits (drusen) under retinal pigment epithelium (especially in the macula) that eventually coalesce 3) causes focal detachment of retina with atrophy and resulting visual loss Angiography – 4) best test for exudative variant 5) shows neovascular growth beneath the retinal pigment epithelium (these vessels originate in choroid and grow through defects in Bruch’s membrane 6) vessels leak with subsequent elevation of retina, fibrosis, and disciform macular scar formation
Associated Conditions
ocular histoplasmosis syndrome
Treatment
1) laser ablation of choroidal neovascular growth 2) often requires repeat treatment as neovascularization recurs
Tips for USMLE
if the patient is an 83 year-old man who is otherwise well and is now noted to have central vision loss on his screening eye exam for his driver’s license renewal, think macular degeneration
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