Abstract
A randomised controlled study of photocoagulation compared with no treatment in central retinal vein occlusion is reported. Forty-eight patients were allocated into treated and control groups by a random procedure 3 months after their first visual symptoms. For the analysis they were subdivided into (1) ischaemic type, and (2) hyperpermeability-response macular-oedema type of central retinal vein occlusion. In neither group did treatment confer benefit as far as visual acuity was concerned. However, iris, disc, and retinal neovascularisation improved after treatment in the ischaemic group. In addition none of the treated patients progressed to neovascular glaucoma. Macular-oedema improved in treated patients with the hyperpermeability response, but the visual field was affected and atrophic changes at the macular precluded visual improvement. It is concluded that photocoagulation should be used only to prevent complications in the ischaemic type of central retinal vein occlusion. It does not appear to be of value in the hyperpermeability group.