Optic dik and retinal nerve fiber layer damage after tranient central retinal artery occluion: an experimental tudy in rheu monkey

PURPOE: To evaluate the retinal tolerance time to acute ichemic inult in middle-aged or elderly rheu monkey with pre-exiting atherocleroi and arterial hypertenion. METHOD: In 39 eye of 39 middle-aged and elderly rheu monkey with a mean age of 19.5 ± 2.8 year, occluion of the central retinal artery wa produced by temporary clamping of the central retinal artery at it ite of entry into the dural heath of the optic nerve for 97 to 300 minute. tereocopic color fundu photography and fluorecein fundu angiography were performed before central retinal artery occluion and erially thereafter. Retinal nerve fiber layer damage and optic dik change were aeed by comparing morphometric evaluation of the color fundu photograph taken before central retinal artery occluion and color fundu photograph taken at the end of the tudy. REULT: There wa a ignificant correlation between duration of central retinal artery occluion and decreaed viibility of retinal nerve fiber layer (P = .018) and increaing optic dik pallor (P = .014), and a trend between reidual retinal circulation and decreaed viibility of retinal nerve fiber layer (P = .085) and optic dik pallor (P = .162). However, there wa a marked interindividual variation between the length of central retinal artery occluion and degree of increaed optic dik pallor and decreaed viibility of the retinal nerve fiber layer, even among eye with imilar duration of central retinal artery occluion. Complete or almot total optic nerve atrophy and nerve fiber damage were preent in all eye in which the duration of central retinal artery occluion wa 240 minute or more. CONCLUION: The finding of thi tudy, compared with our previou tudy in young healthy rheu monkey, indicate that in middle-aged or elderly atheroclerotic and arterial hypertenive rheu monkey, central retinal artery occluion for le than 100 minute produced no apparent morphometric evidence of optic nerve damage; however, central retinal artery occluion of 105 minute but le than 240 minute produced a variable degree of damage; central retinal artery occluion for 240 minute or more produced total or almot total optic nerve atrophy and nerve fiber damage