Postoperative inner nuclear layer microcysts affecting long-term visual outcomes after epiretinal membrane surgery

Purpose: To investigate the risk factors and long-term visual impact of microcysts in the inner nuclear layer developed after epiretinal membrane (ERM) surgery. Methods: This study used a retrospective review of medical records, operative video and images of patients who had undergone idiopathic ERM surgery with more than 12 months of follow-up. Results: This study enrolled 44 patients (44 eyes) with ERM and a mean follow-up period of 30.2 months. The visual acuity improved from a mean of 6/22.8 to 6/12 (P < 0.001). Results indicated that a final visual acuity greater than 0.5 was associated with younger age, better preoperative visual acuity, a complete postoperative inner segment and outer segment line, and absence of inner nuclear layer microcysts. The visual acuity difference between patients with and without inner nuclear layer microcysts emerged in the first month and continued throughout the entire study period. Shorter duration of visual symptoms, more severe grade of ERM with paravascular abnormalities, and retinal petechiae immediately after the peeling of the ERM are risk factors of microcysts. Conclusion: This study suggests that inner nuclear layer microcysts are induced shortly after surgery and have long-term visual effects. Factors associated with this side effect suggest that severity, acuteness, and adhesiveness of ERM may play a significant role in visual outcomes.