Evaluation of Anatomical and Functional Outcome of Epiretinal Membrane Surgery in Idiopathic Epiretinal Membrane Patients

Objective To evaluate the anatomical and functional outcomes of an idiopathic epiretinal membrane (ERM) between the observation group and intervention group at six months postoperative. Design Prospective cohort study. Participants Patients who met the clinical diagnosis of idiopathic ERM in the age frame of 18-80 years; patients with reduced visual acuity (VA), with best corrected VA of 0.2 LogMar or worse, with symptoms of significant metamorphopsia, who visited our center from June 2021 to June 2022. Methods All idiopathic ERM patients who fulfilled the inclusion criteria were selected. The data recorded included the year of ERM diagnosis, duration of symptoms, age at diagnosis, gender, ethnicity, and presence of other ocular pathologies. Corrected VA, lens status, ERM configuration, and central subfield mean thickness (CST) in spectral domain-optical coherence tomography (SD-OCT), ellipsoid zone integrity (EZ), and disorganized retinal inner layer (DRIL) were recorded for all patients at diagnosis, as well as 3 and 6 months after diagnosis for non-operated patients. For patients who underwent surgery (pars plana vitrectomy (PPV), internal limiting membrane (ILM), and ERM peel), data were recorded similarly with additional data on the type of surgery (vitrectomy or combined phaco vitrectomy) and the development of intra or post-surgical complications. Patients receive information on the symptoms associated with ERM, treatment options, and disease progression. After counseling, the patient makes informed consent to the treatment plan. Patients are seen in the 3rd and 6th month from diagnosis. Combined phaco vitrectomy is performed if there is also significant lens opacity. Main outcome measures VA, CST, EZ, and DRIL at diagnosis and 6 months. Results Sixty subjects (30 interventional and 30 observational arms) were recruited for this study. The mean age in the intervention and observation groups was 62.70 and 64.10 years, respectively. Most ERM patients were female in the intervention group compared to males with 55.2% and 45.2% respectively. The mean pre-op CST was 410.03 μm in the intervention group compared to the pre-op CST 357.13 μm observation group. There were significantly different among groups in pre-op CST (p=0.009) using the independent T-test. Furthermore, the mean difference and 95% confidence interval in post-op CST were -69.67 (-99.17, -40.17). There were significant differences among groups in post-op CST (p<0.001) using the independent T-test. Meanwhile, there is no significant association of DRIL between both groups (p=0.23), with 95% CI of mean difference (-0.13, -0.01) using repeated measure analysis of variance (ANOVA) test. There was a significant association of EZ integrity between groups (p=<0.001), 95% CI of mean difference: (-0.13, -0.01) using a repeated measure ANOVA test. Furthermore, the mean post-op VA between pre and post-op VA was significantly different (p<0.001), with a 95% CI of mean difference (-0.85, -0.28). Finally, there is a significant factor association between the duration of ERM and post-op VA (b=.023, 95% CI .001, .05, p<0.05) with our patients. Conclusion ERM surgery has shown positive outcomes on anatomical and functional aspects with minimal safety-related risks. It is evident that a longer duration of ERM does give a minimal impact on the outcome. SD-OCT biomarkers, such as CST, EZ, and DRIL, can be used as reliable prognosticators in decision-making for surgical intervention.