Asymmetric retinopathy in patients with diabetes mellitus.

We reviewed retrospectively the records of 57 diabetic patients with asymmetric retinopathy persisting for two years or more (mean, 4.8 years) to identify intraocular risk and protective factors for the development of proliferative retinopathy. For each patient in this series, the more severely affected eye had proliferative retinopathy and the fellow eye had either background diabetic retinopathy or no retinopathy. Branch vein occlusion (P = .016) was identified as a statistically significant risk factor for proliferative retinopathy and chorioretinal scarring (P = .031) was found to be a statistically significant protective intraocular factor. In 34 patients with long-standing asymmetric retinopathy, no intraocular risk or protective factors were identified.