Panretinal Photocoagulation for Proliferative Diabetic Retinopathy

A 55-year-old man with a 20-year history of type 2 diabetes mellitus was referred to a retina specialist after noticing a few black floaters in his left eye for the preceding week. His glycated hemoglobin level was 8.2%. He had no history of laser treatment for proliferative diabetic retinopathy in either eye. Ophthalmoscopic examination of the right eye showed venous beading, intraretinal microvascular abnormalities, and no macular edema. Ophthalmoscopic examination of the left eye showed extensive neovascularization of the disk, consisting of new vessels extending beyond the optic disk in all directions (Fig. 1A). The retina specialist diagnosed severe nonproliferative diabetic retinopathy in the right eye and high-risk proliferative diabetic retinopathy in the left eye, with no macular edema in either eye. The specialist recommended prompt initiation of panretinal photocoagulation in the left eye.