Caue of evere viual lo in the early treatment diabetic retinopathy tudy: ETDR report no. 24 Original Reearch Article

PURPOE: To decribe the caue of and rik factor for peritent evere viual lo occurring in the Early Treatment Diabetic Retinopathy tudy (ETDR). METHOD: The ETDR wa a randomized clinical trial invetigating photocoagulation and apirin in 3,711 peron with mild to evere nonproliferative or early proliferative diabetic retinopathy. evere viual lo, defined a bet-corrected viual acuity of le than 5/200 on at leat two conecutive 4-month follow-up viit, developed in 257 eye (219 peron). Of thee 257 eye, 149 (127 peron) did not recover to 5/200 or better at any viit (peritent evere viual lo). Ocular characteritic of thee eye were compared with thoe of eye with evere viual lo that improved to 5/200 or better at any ubequent viit. Characteritic of patient with evere viual lo that did and did not improve and thoe without evere viual lo were alo compared. REULT: evere viual lo that perited developed in 149 eye of 127 peron. In order of decreaing frequency, reaon recorded for peritent viual lo included vitreou or preretinal hemorrhage, macular edema or macular pigmentary change related to macular edema, macular or retinal detachment, and neovacular glaucoma. Compared with all patient without peritent evere viual lo, patient with peritent evere viual lo had higher mean level of hemoglobin A1c (10.4% v 9.7%; P = .001) and higher level of choleterol (244.1 v 228.5 mg/dl; P = .0081) at baeline. Otherwie, patient with peritent evere viual lo were imilar to patient with evere viual lo that improved and to thoe without evere viual lo. CONCLUION: Peritent evere viual lo wa an infrequent occurrence in the ETDR. It leading caue wa vitreou or preretinal hemorrhage, followed by macular edema or macular pigmentary change related to macular edema and retinal detachment. The low frequency of peritent evere viual lo in the ETDR i mot likely related to the nearly univeral intervention with catter photocoagulation (either before or oon after high-rik proliferative diabetic retinopathy developed) and the intervention with vitreou urgery when clinically indicated.