Contrast sensitivity evaluation in high risk proliferative diabetic retinopathy treated with panretinal photocoagulation associated or not with intravitreal bevacizumab injections: a randomised clinical trial

Purpose To compare the effect on contrast sensitivity (CS) measurements of panretinal photocoagulation (PRP) associated with intravitreal bevacizumab (IVB) injections versus PRP alone in high risk proliferative diabetic retinopathy (HR-PDR). Design Prospective, randomised, masked, controlled trial. Participants 42 patients with HR-PDR with visual acuity ≥20/200. Methods Eyes were randomised to one of two groups: one underwent PRP and IVB injections (study group) and the other PRP alone (control group). PRP was performed three times during the study and IVB injection was administered twice. Main outcome measures Mean change in CS threshold scores between and within groups, from baseline to 6 months. Results Seven patients presented with vitreous haemorrhage and were removed from the study. Mean results for CS threshold (at 1.5, 3, 6, 12 and 18 cycles per degree (cpd) frequencies) for patients with and without diabetic macular oedema showed no significant differences (p>0.05 for all comparisons) between the two groups. In 35 eyes in the control group, compared with baseline values, there was significant worsening (p