Abstract: Objective To observe the clinical effect of vitrectomy (PPV) combined with modified internal limiting membrane (ILM) flap in the treatment of large diameter idiopathic macular hole (IMH). Design Randomized controlled trial. Participants A total of 60 IMH patients were included in the study, including 7 males (7 eyes), aged 46-73 years. The maximum diameters of macular hole were all ≥600 μm. Methods 60 patients were randomly divided into group A and group B. 30 patients in each group were treated with PPV combined with ILM tamponade in group A, group B was treated with single ILM flap coverage. Main Outcome Measures BCVA, CMT, the clarity and regularity of the outer layer of the retina, the retention of subretinal hyperreflexive substances in the macular region and the scar in the macular region were measured before, 1 week, 1, 3 and 6 months after the operation. Results All postoperative fissures were closed in both groups. The postoperative BCVA at the corresponding time points between the two groups was not statistically significant (all P>0.05). There was a difference in BCVA from 1 month postoperatively (1.17±0.29), (1.13±0.25) compared to BCVA at 1 week postoperatively (1.47±0.38), (1.45±0.33), (1.40±0.34), and (1.39±0.31) within the two groups (all P<0.01), and within the group at 3 months postoperatively (0.88±0.26), (0.85±0.27), 6 months (0.81±0.24), (0.78±0.21) compared with 1 month postoperatively also differed (all P<0.01). There was no significant difference between 3 and 6 months postoperatively (all P>0.05). The results of CMT in both groups basically did not change significantly (all P>0.05) preoperatively, at 1 month postoperatively, and at about 3 months postoperatively. However, the CMT in the group was significantly thickened at 1 week postoperatively (275.34±18.76) and (266.58±18.26) relative to preoperatively (254.32±17.83) and (252.17±17.12) (all P<0.01), and at 6 months postoperatively (238.49±24.43) and (236.52±22.71) compared to preoperatively compared with the preoperative period (all P<0.01). There was no statistical difference between the two groups in the time points corresponding to the discernibility of the outer layer structure and smoothness and regularity after surgery (all P>0.05). All 60 patients showed hyperreflesive signals preoperation. After operation, 6 cases in the two groups still showed obvious hyperreflexive signals in the macular structure, and the remaining 54 cases gradually became smaller and disappeared in 1~3 months after operation. Conclusion PPV combined with ILM flap has a significant clinical effect in the treatment of large-diameter IMH. It can effectively close the hole and promote the recovery of macular structure. (Ophthalmol CHN, 2022, 31: 369-374)

Key words: idiopathic macular hole, monolayer ILM flap, outer retina structure