Anterior ischemic optic neuropathy. IX. Cup-to-disc ratio and its role in pathogenesis.
The optic disc appearance in the normal fellow eye of 126 patients with nonarteritic anterior ischemic optic neuropathy (n-AION) was compared with the discs in 23 patients with arteritic AION (a-AION) and 122 normal subjects. The number of discs with no cup was significantly greater (P less than 0.001) and the number of discs with a large cup was significantly fewer (P less than 0.001) in the n-AION group compared to the other two groups. No significant differences were found in cup size between the a-AION and normal groups. The pathogenesis of n-AION appears to be multifactorial. There is overwhelming evidence that ischemia is the primary factor. The size of the optic disc also plays a role, probably through a compressive effect at the level of the lamina cribrosa on axons subjected to ischemia. In contrast, a-AION occurs from posterior ciliary artery occlusion and disc size is not a factor.
Beck
R W
RW
W.K. Kellogg Eye Center, University of Michigan, Ann Arbor.
Servais
G E
GE
Hayreh
S S
SS
D000328:Adult; D001766:Blindness / Q000473:pathology; D005260:Female; D006801:Humans; D007511:Ischemia / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000098:blood supply* / Q000473:pathology; D009900:Optic Nerve / Q000098:blood supply* / Q000473:pathology; D009902:Optic Neuritis / Q000473:pathology*; D010211:Papilledema / Q000473:pathology