Materials and Methods: iERM patients admitted to the retina outpatient clinic were divided into stages by OCT and best corrected visual acuity (BCVA), OCT parameters (central macular thickness (CMT), macular volume (MV), maximum retinal thickness (MRT), outer nuclear layer (ONL) and ectopic inner foveal layer (EIFL) thickness) were determined and biomarkers (cotton ball sign, cystoid macular edema (CME), vitreomacular traction (VMT), retinoschisis, external limiting membrane-ellipsoid zone (ELM-EZ) disruption, disorganized retinal inner layers (DRIL)) were evaluated.

Results: There was a statistically significant difference between the patients regarding BCVA, CMT, MV, MRT, ONL, and EIFL thickness according to their OCT stages. (p<0.0001) BCVA was the lowest in Stage 4, with the highest CMT, MV, and MRT values. A statistically significant positive correlation was found between the patient?s BCVA and CMT, MV, MRT, OCT stage, ONL, and EIFL thickness values. (p<0.05) Visual acuity was significantly lower in patients with VMT, retinoschisis, ELM-EZ disruption, and DRIL than those without. (p=0.017, p=0.002, p=0.043, p=0.02, respectively) No statistically significant difference was found between the patients regarding BCVA according to the presence of cotton ball sign and CME. (p>0.05) No statistically significant difference was found between the presence of cotton ball sign and gender, hypertension, diabetes, lens status, OCT stage, ONL, and EIFL thickness. (p>0.05)

Conclusion: Retinoschisis, VMT, ELM-EZ defects, and DRIL should be considered negative prognostic factors for visual acuity. The presence of cotton ball sign and CME was not found to affect visual acuity in this study. Keywords : Cotton ball sign, Ectopic inner foveal layers, Epiretinal membrane, Optical coherence tomography, Outer nuclear layer