• Central macular thickening [ Time Frame: 2 weeks after each laser session and 1 and 2 months after last laser session ] [ Designated as safety issue: No ]
  

• Best corrected visual acuity [ Time Frame: 2 weeks after each laser session, 1, 2 and 3 months after pan-retinal photocoagulation is completed ] [ Designated as safety issue: Yes ]
  

Objective: To evaluate the effect of topical nepafenac 0.1 %, in preventing and in treating macular thickening related to pan-retinal photocoagulation in diabetic patients. Material and methods: This is a prospective, longitudinal, and controlled study in patients with diabetic retinopathy (severe non-proliferative and proliferative retinopathy), with a symmetric severity in both eyes and without a clinical significant macular edema. The best corrected visual acuity (BCVA) in all patients was 20/80 or better. All patients will undergo pan-retinal photocoagulation in three different sessions (with 2 weeks in apart between them). Each patient will receive topical nepafenac 0.1% (qid) on one eye, and placebo (qid) at the fellow eye, starting 1 week before the first retinal photocoagulation session and continued for 9 weeks ( ending 4 weeks after pan-retinal photocoagulation is completed). Spectral domain OCT and BCVA in ETDRS scale will be performed before and at 2 weeks after each laser session, and at 1, 2 and 3 months after treatment completed. BCVA and OCT outcomes of each studied period will be compared on both eyes, and side effects will be recorded.