The effect of panretinal photocoagulation on optic nerve cupping

Panretinal photocoagulation (PRP) can produce damage to all layers of the retina, including the nerve fiber layer. The hypothesis that these changes in the nerve fiber layer may alter the contour of the optic disc and change the cup-to-disc (C/D) ratio was tested. In a masked retrospective study, the authors evaluated the stereoscopic disc photographs of 100 patients with proliferative diabetic retinopathy (PDR) before and 1 year after undergoing PRP. The fellow untreated eyes were used as controls. Neither argon nor xenon PRP produced a significant change in the C/D ratio.