Macular epiretinal membrane in high myopia: timing and prognosis of pars plana vitrectomy surgery

AIM: To investigate the outcomes and prognosis of macular epiretinal membrane (ERM) after pars plana vitrectomy (PPV) in patients with high myopia (HM), focusing on the optimal timing of surgery and its impact on prognosis. METHODS: The clinical data of 50 eyes from 49 patients diagnosed with ERM, who were highly myopic and underwent PPV were retrospectively analyzed. The patients with ERM were classified into five groups based on the characteristics associated with different levels of myopic traction maculopathy. Group 1: Simple ERM without complex vertical and tangential direction traction on retina on optical coherence tomography (OCT) image; Group 2: ERM with obvious macular foveal schisis, without macular hole (MH); Group 3: ERM with inner lamellar MH, with or without macular foveal schisis; Group 4: ERM with outer lamellar MH, with or without foveal retinal detachment (RD); Group 5: ERM with full-thickness MH. Baseline characteristics, changes in best corrected visual acuity (BCVA) before and after surgery, and anatomical characteristics through spectral domain OCT were compared. RESULTS: The 50 eyes were followed for 6mo, with an average age of 58.66y and an average axial length (AL) of 28.69 mm. Among the five groups, postoperative logMAR BCVA improved (P<0.05). Group 1 had better mean BCVA at baseline (0.59±0.36) and at 6mo postoperatively (0.16±0.22) compared to the other groups, while Group 5 had worse mean BCVA at baseline (1.68±0.45) and at 6mo postoperatively (1.27±0.64). There were no statistically significant differences in sex, age or AL between the groups (P>0.05). OCT showed that Groups 4 and 5 exhibited poorer macular anatomy compared to the other three groups, as evidenced by lower rates of central retinal reattachment (64.3% in Group 4, 86.7% in Group 5) and integrity of the inner segment/outer segment of photoreceptor junction (28.6% in Group 4, 26.7% in Group 5). CONCLUSION: PPV is an effective treatment for ERM in patients with HM. All groups showed postoperative improvement in BCVA compared to preoperative levels, demonstrating the necessity of surgical intervention. Early intervention, particularly before the fourth stage of the disease, may lead to better visual outcomes.