External limiting membrane aperture as a reliable and predictive prognostic factor in macular hole surgery

Purpose: To evaluate the role of external limiting membrane aperture (ELMA) as a prognostic factor for the anatomical and functional outcomes of full thickness macular hole (FTMH) surgery. Design: Retrospective. Methods: 120 eyes of 120 patients who underwent surgery for idiopathic FTMH were enrolled. Best corrected visual acuity (BCVA) and spectral-domain optical coherence tomography (SD-OCT) scans were evaluated preoperatively and postoperatively at 3 and 12 months. Statistical analysis was performed to correlate the following preoperative parameters with 12-months postoperative BCVA and anatomical results: ELMA, apical hole diameter (AD), base hole diameter (BD), macular hole index (MHI), tractional hole index (THI), height (H), diameter hole index (DHI), hole form factor (HFF) and preoperative BCVA. Results: Primary successful MH closure was achieved in all the eyes. Postoperative BCVA showed a statistically significant increase from a preoperative logMAR median (IQR) value of 0.70 (0.52–1.00) to 0.18 (0.10–0.34) at 3 months and 0.16 (0.05–0.30) at 12 months. As demonstrated by ROC curves analysis, ELMA revealed to be a good predictor for 1B and 1C types of MH closure when its value was greater than 369 µm. Moreover, ELMA sizes above 369 µm were strongly associated with a postoperative BCVA less than 20/40. Conclusions: ELMA appears to be a reliable prognostic factor for postoperative anatomical and functional outcome in FTMH surgery.