Effect of panretinal photocoagulation on optic nerve head blood flow with OCT angiography in patients with diabetic retinopathy

OBJECTIVE: To investigate the effect of pan retinal photocoagulation (PRP) on Optic nerve head blood flow with OCT angiography in patients with proliferative diabetic retinopathy. METHODS: This prospective interventional study was conducted at Eye Unit III, Institute of Ophthalmology, Mayo Hospital, Lahore, over a period of seven months i.e. from 10th May 2019 to 10(th) November 2019. Thirty-five patients having proliferative diabetic retinopathy were included in this study. Ocular blood flow was measured with OCT Angiography, then pan retinal photocoagulation was performed and patients were called for follow-up after one month and ocular blood flow was measured again with OCT Angiography. The difference in the blood flow was calculated. Frequencies and percentages were calculated for the categorical data and mean and standard deviations were calculated for the continuous data. Wilcoxon matched-pairs signed rank test was performed and effects of PRP on blood flow were compared. Significance level was taken as p≤0.05. RESULTS: Out of 35 patients, 30 patients (85.71%) had decreased post PRP blood flow, four patients (11.43%) had increased post PRP blood flow and one patient (2.86%) did not have any effect. CONCLUSION: OCT angiography revealed there is significantly reduced optic nerve head blood flow in PRP treated eyes compared to non-PRP treated eyes.