Comparing the inverted internal limiting membrane flap technique with internal limiting membrane insertion technique for treatment of large macular holes.

Purpose: To compare the anatomical and functional outcomes of the inverted internal limiting membrane(ILM) flap technique and ILM insertion technique for the treatment of large macular holes(MHs).

Methods: Seventy-four consecutive eyes with large MHs(minimum diameter ≥400 µm) were included. All patients underwent 25-gauge pars plana vitrectomy(PPV) with either inverted ILM flap technique(n=40) or ILM insertion technique(n=34). Swept source optical coherence tomography (SS-OCT) was performed before surgery and 12 months postoperatively. The rate of MH closure, postoperative best corrected visual acuity(BCVA) and SS-OCT findings were evaluated at 12 months after surgery.

Results: MH closure was achieved in 34 eyes(85%) of the inverted ILM flap group and in 30 eyes(88.2%) of the ILM insertion group.There was no significant difference in the rate of MH closure(P=0.685). The mean BCVA improved from 1.30±0.81 logMAR (Snellen: 20/400) at baseline to 0.64±0.67 logMAR (Snellen: 20/87) at 12 months in the inverted ILM flap group, which was significanlty better than that in the insertion ILM group(P=0.047). At 12 months, the mean external limiting membrane (ELM) defect sizes was 106.68±196.25 µm in the inverted ILM flap group and 234.12±296.06 µm in the ILM insertion group, whereas the mean ellipsoid zone (EZ) defect sizes were 167.08±223.08 µm and 261.58±290.92 µm, respectively. The mean ELM defect sizes were significantly smaller in the inverted ILM flap group than in the ILM insertion group(p=0.039). However, there was no significant difference in mean EZ defect sizes between the two groups(P=0.160).

Conclusion: Both the inverted ILM flap and the insertion ILM techniques were associated with high rates of MH closure in large MHs. The inverted ILM flap technique seemed to be more effective surgery for large MHs compared with the ILM insertion techniques in improving visual outcomes.