This study compares the anatomical and visual outcomes in a large series of patients affected by idiopathic macular holes larger than 400 µm treated using pars plana vitrectomy and gas tamponade combined with internal limiting membrane (ILM) peeling or the inverted internal limiting membrane flap technique. A part of the participants will receive internal limiting membrane peeling,whil the other will receive the inverted internal limiting membrane flap technique.

Vitrectomy is the standard treatment for idiopathic macular holes (IMHs) and is combined with removal of the internal limiting membrane (ILM) to improve anatomical outcomes.However, surgical closure is not achieved after a single operation in all cases, and patients with long-standing MHs or highly myopic eyes are challenging to treat.Various surgical strategies have been introduced to improve postoperative outcomes for these cases. Michalewska et al. have reported an inverted ILM flap technique for large MHs. The ILM around the MH was left to cover or fill the hole and showed a better anatomical closure rate and visual outcome than ILM peeling for large MHs. Nevertheless, the functional and anatomic outcomes of the ILM flap technique have not been investigated as extensively as the ILM peeling technique and have yet to be confirmed by research comparing the ILM flap technique with the conventional procedure.

Inclusion Criteria:

• idiopathic MHs, a minimum hole diameter of ≥ 400 μm, and follow-up for at least 3 months after vitrectomy.

Exclusion Criteria:

• High myopia (≥6 diopters,AL≥26.5mm), increased intraocular pressure (IOP, >21 mm Hg) or glaucoma, severe cataract, severe systemic conditions that prevent surgery, and history of ocular trauma, intraocular inflammation, retinal vascular disease, or previous ocular surgery.