Extent of Internal Limiting Membrane Peeling and its Impact on Macular Hole Surgery Outcomes: A Randomized Trial.

Purpose: To identify whether and how outcomes of macular hole (MH) surgery are influenced by the extent of internal limiting membrane (ILM) peeling.

Design: Randomized clinical trial.

Methods: This study involved 65 eyes from 65 patients who underwent surgery for idiopathic MH. ILM was peeled with a radius of either 0.75 disc diameter (small-extent group, SEG) or 1.5 disc diameter (large-extent group, LEG), according to the randomization. Anatomic success, visual acuity, and metamorphopsia score (M-score) were measured at 2- and 6-month postoperative visits. The distance between the foveal center and the parafoveal edge of the outer plexiform layer on optical coherence tomography was measured in 4 directions, and further distance increases in certain directions were defined as asymmetric elongation of foveal tissue.

Results: Complete closure of the MH was observed after initial operation in 97.0% of eyes in both groups. The mean visual improvement at 6 months after surgery was 20.4 ± 12.8 and 19.1 ± 10.8 ETDRS letters in SEG and LEG, respectively (P = .452). The mean amount of improvement in M-score was 0.26 ± 0.55 in SEG and 0.50 ± 0.53 in LEG (P = .039). There was a difference in the mean degree of asymmetric elongation between the 2 groups (22.5% ± 10.8% in SEG vs 13.4% ± 5.8% in LEG, P = .001). And there was inverse correlation between the mean degree of asymmetric elongation and the amount of improvement in M-score at 6 months postoperatively (P < .001).

Conclusion: Larger extent of ILM peeling during MH surgery is beneficial with respect to reduction of metamorphopsia, alleviating asymmetric elongation of foveal tissue.