ObjectiveTo observe the effectiveness and safety of pars plana vitrectomy (PPV) combined with inner limiting membrane (ILM) removal and 41G microneedle subretinal injection of balanced salt solution (BSS) in the treatment of refractory macular hole. MethodsA prospective clinical study. From January to June 2023, 20 cases (20 eyes) of refractory macular hole patients diagnosed through examination at The Affiliated Eye Hospital of Nanchang University were included in the study. The basal diameter of the affected eye's basal diameter (BD) was ＞1 000 μm. Macular hole index (MHI) was ＜0.5. The affected eye received treatment with 23G PPV combined with ILM removal and 41G microneedle subretinal injection of BSS. Best corrected visual acuity (BCVA), microperimetry, and optical coherence tomography angiography (OCTA) were performed before and 1, 2, 3, and 6 months after surgery for the affected eye. BCVA examination was performed using standard logarithmic visual acuity chart, and convert it to logarithmic minimum resolution angle (logMAR) visual acuity for statistical purposes. MP-3 microperimetry was used for micro view examination, record the mean sensitivity (MS) of the retinal within a 12° range of the fovea. OCTA was used to measure the area of the avascular zone of the macula (FAZ), perimeter of the FAZ (PERIM), retinal vascular length density (VLD), and vascular perfusion density (VPD). The changes in BCVA, MS, FAZ area, PERIM, VLD, VPD before and after surgery were compared and analyzed. After the same time, the closure of macular hole and the occurrence of complications after surgery were observed. Single factor analysis of variance was used to compare the observation indicators at different times before and after surgery. The correlation between various observation indicators and preoperative minimum diameter (MD), BD, and hiatus height at 6 months after surgery were analyzed using Pearson correlation analysis. ResultsAmong the 20 cases with 20 eyes, there were 2 males with 2 eyes and 18 females with 18 eyes. Age was (61.45±8.56) years old. The logMAR BCVA, MS, FAZ area, PERIM, VLD, and VPD of the affected eye were 1.46±0.21, (16.20±5.81) dB、(0.40±0.17) mm2, (2.89±0.99) mm, (6.23±3.59) mm−1, (0.17±0.10)%, respectively. Six months after surgery, out of 20 eyes, macular hole closure and incomplete closure were 18 (90.0%, 18 /20) and 2 (10.0%, 2 /20) eyes, respectively. The logMAR BCVA, MS, FAZ area, PERIM, VLD, and VPD were 0.80±0.20, (22.20±4.60) dB, (0.18±0.10) mm2, (1.83±0.80) mm, (9.54±2.88) mm−1, (0.31±0.14)%. Compared with before surgery, the differences were statistically significant (P＜0.05). The correlation analysis results showed a positive correlation (P＜0.05) between preoperative BD and postoperative 6-month PERIM and VPD. There was a negative correlation between preoperative MD and postoperative VLD at 6 months (P＜0.05). There was a negative correlation between preoperative MHI and logMAR BCVA and VPD at 6 months after surgery (P＜0.05). No complications such as elevated or decreased intraocular pressure, damage to retinal pigment epithelium, retinal hemorrhage, endophthalmitis, or retinal detachment occurred after surgery in all affected eyes. ConclusionMinimally invasive PPV combined with ILM removal and 41G microneedle subretinal injection of BSS can effectively improve the closure rate of refractory macular hole patients in the short term, improve vision, and have good safety.