Objective To explore the efficacy and safety of pars plan vitrectomy(PPV)combined with internal limit-ing membrane(ILM)covering surgery in patients with large-diameter idiopathic macular holes(IMH)using optical coher-ence tomography angiography(OCTA)and microperimetry.Methods Twenty-three eyes of 23 patients with large-diame-ter IMH treated at the Eye Hospital Affiliated with Nanchang University from February 2023 to July 2023 were selected.The patients'best-corrected visual acuity(BCVA),hole closure rate,microcirculation[perfusion density at the superficial cap-illary plexus(PSCP)and vascular density at the retinal superficial capillary plexus(VSCP)]in the macular area(divided into central,inner and outer regions),macular sensitivity(MS),fixation stability,and foveal avascular zone(FAZ)area were observed before surgery and at 1 week,1 month,3 months,and 6 months after surgery.Changes in eye parameters before and after surgery were compared,and the correlation between parameters was analyzed.Results After a 6-month follow-up,all macular holes in the affected eyes were closed,with a closure rate of 100％.Compared to before surgery,the BCVA of the patients improved gradually at 1 week,1 month,3 months,and 6 months after surgery,and the differ-ences between any two time points were statistically significant(all P＜0.05).The FAZ area decreased at 1 week,1 month,3 months,and 6 months after surgery compared to before surgery,and the differences were statistically significant(all P＜0.05).The VSCP in the three regions showed a decrease at 1 week postoperatively and an increase at 6 months postoperatively compared to before surgery,and the differences were statistically significant(both P＜0.05).The PSCP in-creased at 3 months and 6 months postoperatively compared to before surgery,with statistically significant differences(both P＜0.05).The 12° MS increased at 1 month,3 months,and 6 months after surgery compared to before surgery,with statistically significant differences(all P＜0.05).The proportions of fixation points within 2° and 4° increased at 1 month,3 months,and 6 months postoperatively compared to before surgery,with statistically significant differences(all P＜0.05).The proportion of fixation points within 4° increased at 1 week postoperatively compared to before surgery,with a statistically significant difference(P＜0.05).Correlation analysis showed that preoperative MS and the proportion of fixa-tion points within 2° were negatively correlated with BCVA(logMAR)at 6 months postoperatively(r=-0.819,-0.790,both P＜0.05),while preoperative FAZ area and minimum hole diameter were positively correlated with BCVA(logMAR)at 6 months postoperatively(r=0.596,0.853,both P＜0.05).The preoperative VSCP in the inner and outer regions were negatively correlated with BCVA(logMAR)at 6 months postoperatively(r=-0.521,-0.570,both P＜0.05).Conclu-sion The results of OCTA and microperimetry show that after treatment with PPV and ILM covering surgery,the closure rate of large-diameter IMH is good,and all indicators have improved compared to before surgery.