Effect of axial length and age on the visual outcome of patients with idiopathic epiretinal membrane after pars plana vitrectomy

We evaluated predictive factors for visual outcomes in patients with idiopathic epiretinal membrane (iERM) after pars plana vitrectomy (PPV). Clinical records for 114 eyes (114 patients, mean age: 70.6 years) with iERM treated by PPV between March 2012 and March 2018 were retrospectively reviewed. Overall, the mean postoperative best-corrected visual acuity (BCVA) and central retinal thickness measured by optical coherence tomography improved as early as 1 month after surgery, and further improved until 3 months (P < 0.01). Multiple linear regression analyses adjusted for the preoperative BCVA showed that older age (B, 0.010; 95% confidence interval, 0.003 to 0.016; P = 0.003) and a shorter axial length (AL; B, -0.059; 95% confidence interval, -0.099 to -0.019; P= 0.005) predicted worse postoperative BCVA. The Mann-Whitney U test showed that the postoperative BCVA was worse in eyes with AL < 23.6 mm than in eyes with AL >= 23.6 mm (P = 0.037), and in patients aged >= 69 years than in patients aged <69 years (P = 0.024). The findings may help in evaluating surgical indications for each patient to obtain satisfactory outcomes, irrespective of the preoperative BCVA.