Abstract： Objective:To observe the healing morphology, macular microstructure and visual function of idiopathic macular hole (IMH) after pars plana vitrectomy (PPV) combined with internal limiting membrane (ILM) flap.Methods:Retrospective case study. From 2016 to 2018, 39 eyes of 39 patients with IMH diagnosed in Tianjin Eye Hospital were included in the study. Among them, there were 4 eyes in 4 males and 35 eyes in 35 females, with an average age of 64.56±7.2 years. BCVA, OCT, OCT angiography (OCTA) and MAIA microperimetry examination were performed in all patients. BCVA examination was performed with the international standard visual acuity chart, which was converted to logMAR visual acuity when recording. All patients underwent PPV combined with ILM flap covering and air tamponade. According to the characteristics of OCT images postoperatively, the eyes were divided into U-shaped closed group, V-shaped closed group, irregular closed group and flat closed group, with 26, 5, 7 and 1 eyes respectively. There was a significant difference in the minimum hole diameter ( F=5.118, P=0.005) and macular hole classification ( F=3.608, P=0.024). The shallow capillary layer (SCP) blood flow density in the U-shaped closure group was significantly higher than that in the V-shaped closure group, the irregular closure group and the flat closure group (t=2.079, 2.368; P=0.047, 0.025). At 1, 3, 6 months after the operation, the same equipment and methods were used for relevant examination. The blood flow density of BCVA, SCP, perimeter of foveal avascular zone (PERIM) and mean sensitivity (MS) were compared before and after operation. Independent sample t-test was used for quantitative data comparison between different groups, and χ2 test was used for counting data comparison. Results:Six months after operation, the logMAR of the eyes in the U-shaped closure group was -0.75±0.29 higher than that before operation, and was better than that in the V-shaped closure group, the irregular closure group and the flat closure group ( t=-2.974, -2.518; P=0.006, 0.018). The integrity of external limiting membrane (ELM) and ellipsoid in U-shaped closed group was significantly higher than that in V-shaped closed group, irregular closed group and flat closed group ( χ2=15.229, 10.809; P=0.020, 0.013). The percentage of macular central fovea reflex mass in the U-shaped closed group was significantly lower than that in the V-shaped closed group, irregular closed group and flat closed group ( χ2=20.107, P=0.000). PERIM in U-shaped closure group was smaller than that in V-shaped closure group, irregular closure group and flat closure group, and the difference was statistically significant ( t=-3.391, -2.427; P=0.002, 0.022). The total MS of macular area 10° in the U-shaped closure group was significantly higher than that in the other V-shaped closure group, irregular closure group and flat closure group ( t=2.939, 2.811; P=0.001, 0.001). Conclusion:After IMH operation, the U-shaped closure showed better BCVA and macular light sensitivity, the proportion of ELM and ellipsoid to restore structural integrity are higher, PERIM is smaller, and there are fewer macular fovea strong reflex masses.