Risk of retinal neovascularization in the second eye in patients with proliferative diabetic retinopathy.

Purpose: This study aimed to evaluate the risk of proliferative diabetic retinopathy (DR) in the fellow eye of an eye with existing proliferative DR.
Methods: Our DR screening programme database listed 1513 diabetes patients alive at the time of the study. Seventy-six had proliferative DR in one or both eyes.
Results: In 28 of the 76 (37%) diabetes patients, proliferative DR was diagnosed in both eyes at the same examination. Another 28 patients developed proliferative DR in the second eye within 5 years of its diagnosis in the first eye, bringing the total number of diabetes patients with proliferative DR in both eyes at 5 years to 56 (74%). Almost all the diabetes patients eventually developed proliferative DR in the second eye. The median duration of diabetes before the development of proliferative retinopathy was 19 years for type 1 and 14 years for type 2 diabetes.
Conclusions: Proliferative DR is a bilateral disease. Diabetes patients with proliferative DR in one eye are at high risk of developing neovascularization in the second eye and close follow-up is recommended.