PURPOSE:To investigate optical coherence tomography (OCT) biomarker data on visual recovery in treatment-naïve diabetic macular edema (DME) and follow the results of intravitreal ranibizumab (RNB), aflibercept (AFL), and dexamethasone (DEX) implant administration within the 1st year of the pro re nata treatment regimen.METHODS:One hundred and twenty eyes of 102 patients were enrolled in the study. The patients medical records were analyzed retrospectively. Best-corrected visual acuity (BCVA), central macular thickness (CMT), type of DME, presence of subretinal fluid, number and localization of hyperreflective dots, vitreomacular interface disorders, disorganization of the retinal inner layer (DRIL), inner segment/outer segment (IS/OS) junction-external limiting membrane (ELM) status, intraretinal cyst diameter and localization, and subfoveal choroidal thickness were examined in all patients.RESULTS:A statistically significant increase in BCVA and a decrease in CMT were detected in all treatment groups. When cases were evaluated in terms of BCVA before and after treatment, statistically significant differences were observed in the RNB and AFL groups at 1 and 4 months and in the DEX group during the 1st year. In terms of OCT biomarkers, visual recovery was obtained in cases of intact IS/OS-ELM and non-DRIL patients. In the serous macular detachment group, more visual gain was achieved with the RNB (1 and 4 months) and AFL (1, 4, and 6 months) agents compared to the DEX implant. On the other hand, in the group with cystoid macular edema, more visual gain was achieved with RNB compared to the DEX implant in all months, but more visual gain was achieved only in the 1st month with AFL administration.CONCLUSION:Significant improvement was achieved for both BCVA and CMT in all treatment groups. We expect that OCT-based prognostic factors will become more important in the treatment of DME and will be determining factors in the choice of treatment.