Panretinal photocoagulation induced alterations in accommodation, pupillary parameters and contrast sensitivity: A prospective study in patients with proliferative diabetic retinopathy

Diabetic retinopathy is a serious eye disease caused by diabetes, where high blood sugar levels damage the blood vessels in the retina. Oxidative stress induced hyperglycemia is the key event in the pathogenesis of diabetic retinopathy. This damage can lead to vision impairment and, in advanced stages, blindness. Diabetic retinopathy progresses through various stages as non proliferative diabetic retinopathy NPDR and proliferative diabetic retinopathy PDR. Panretinal photocoagulation PRP is a type of laser treatment used to reduce the risk of severe vision loss in patients with proliferative diabetic retinopathy PDR or other retinal diseases. It involves applying controlled laser burns to peripheral retina, promoting selective photocoagulation, significantly reduces the oxygen demand of peripheral retina, leading to decrease production of vascular endothelial growth factor(VEGF) and other angiogenic factors. The  study will evaluate the effect of PRP on accommodation, pupillary parameters and contrast sensitivity before PRP sitting , 1 month and 3 month after completion of PRP. The pupillary parameters will be assessed in photopic, mesopic and scotopic illumination conditions.