Abstract
Abstract: :
Purpose: Advanced age–related macular degeneration (AMD) has been associated with relative afferent pupillary defects, and recently a correlation with glaucomatous disc changes has been proposed. Does optic disc pallor occur in AMD and could this indicate a possible optic neuropathy? Methods: Two–hundred thirty–seven consecutive records of AMD patients were reviewed. Patients with optic neuropathies, diabetic retinopathy, or glaucoma were excluded. Twenty–eight patients met the criteria of "unilateral advanced AMD" by having an exudative lesion or large area of central geographic atrophy in one eye only. Twenty–four patients were classified as "bilateral early AMD"; both eyes had drusen, with or without retinal pigment epithelial abnormalities, but neither eye had subretinal fluid or hemorrhage, pigment epithelial detachments, or large areas of geographic atrophy. Fundus photographs were masked so that only the optic discs were visible. A Neuro–ophthalmologist graded each disc for pallor and cupping. Chi–square analysis was performed to determine whether eyes with advanced AMD demonstrated more temporal pallor than eyes with early AMD and whether glaucomatous cupping was associated with macular degeneration. Results: Fifty–seven percent of patients with unilateral advanced AMD had temporal pallor in the advanced eye. Only 29% of patients with bilateral early AMD had asymmetric disc pallor. The difference between these two groups was statistically significant [p<0.05]. Seventeen percent of eyes had a cup–to–disc ratio >0.5, but there was no association between glaucomatous cupping and the degree of macular degeneration. Conclusions: We found that AMD is associated with optic disc pallor, the hallmark of optic neuropathy. Ischemia is a major cause of optic neuropathy and has also been postulated as one cause of AMD. Patients with AMD have decreased blood flow to the choroid and through the short posterior ciliary arteries and central retinal artery. Decreased perfusion of the optic nerve could explain the temporal pallor observed to a greater extent in eyes with advanced AMD. Interestingly, even patients with early AMD had disc pallor, lending further support to the vascular (ischemia) theory of AMD.
Keywords: neuro–ophthalmology: optic nerve • age–related macular degeneration • blood supply