A RANDOMIZED CLINICAL-TRIAL OF EARLY PANRETINAL PHOTOCOAGULATION FOR ISCHEMIC CENTRAL VEIN OCCLUSION - THE CENTRAL VEIN OCCLUSION STUDY-GROUP-N REPORT

Purpose: To answer whether prophylactic panretinal photocoagulation (P RP) in ischemic central vein occlusion (CVO) prevents development of 2 clock hours of iris neovascularization or any angle neovascularizatio n (TC-INV/ANV) or whether it is more appropriate to apply PRP only whe n TC-INV/ANV occurs. Methods: Multicenter randomized controlled clinic al trial in eyes with ischemic CVO. Eyes were assigned to immediate pr ophylactic PRP (90 eyes) or to frequent close observation (91 eyes), I f TC-INV/ANV developed, untreated eyes received PRP and previously tre ated eyes received supplemental PRP. Results: In both groups, TC-INV/A NV developed less often in prophylactically treated than untreated eye s, but the difference was not statistically significant when adjusted for baseline imbalance. Treatment of TC-INV/ANV was followed by prompt regression (within 1 month) in 18 (56%) of 32 previously untreated ey es and in 4 (22%) of 18 eyes that had had prophylactic treatment, All eyes except eight eventually stabilized without neovascularization. TC -INV/ANV was correlated with the amount of nonperfused retina (P = 0.0 001) and extent of retinal hemorrhage (P = 0.03). Males were at higher risk than females for TC-INV/ANV (P = 0.01), as were patients with oc clusions of less than one month duration (P = 0.01), Conclusions: Prop hylactic PRP does not totally prevent TC-INV/ANV, and prompt regressio n of TC-INV/ANV in response to PRP is more likely to occur in eyes tha t have not been treated previously. The authors recommend careful obse rvation with frequent follow-up examinations in the early months (incl uding undilated slit-lamp examination of the iris and gonioscopy) and prompt PRP of eyes in which TC-INV/ANV develops.