Methods: Patients who have been diagnosed with DME are included in this research. Patients who have been treated with Pro Re Nata (PRN) regime before three months of ranibizumab injection are included in this research. Stage of diabetic retinopathy, type of edema in OCT, epiretinal membrane (ERM) ellipsoid zone damage, and presence of exudate in subretinal fluid and fovea of the patients are determined. The effect of these parameters on final central fovea thickness and best-corrected visual acuity is investigated.

Results: 110 eyes of 65 patients are included in this research. In the multivariate regression analysis, it is found that the poor visual acuity is highly correlated with severe non-proliferative diabetic retinopathy and proliferative diabetic retinopathy, while shows an interrelation with the presence of subretinal fluid in OCT, exudate in fovea, and ellipsoid zone damage (p=0.004, p=0.009, p<0.0001, respectively). A greater decrease in thickness of central fovea is found among the patients with diffuse macular edema, greater central fovea thickness, and without ERM (p=0.018, p=0.001, p=0.003, respectively).

Conclusion: Poor visual acuity in patients who are treated for DME is correlated with advanced stage diabetic retinopathy and especially, ellipsoid zone damage in OCT. While it is found that ERM affects anatomic recovery adversely, there is no significant correlation found between ERM and visual acuity. Keywords : Diabetes mellitus; Macular edema; Optical coherence tomography; Prognostic factors; ranibizumab