Objective To evaluate the efficacy and safety of non-gas-dependent vitrectomy (PPV) assisted by mucoelastic agent (OVD) in ophthalmic surgery combined with internal limiting membrane flipping and covering in the treatment of idiopathic macular holes (IMH). MethodsA retrospective cohort study. From June 2023 to February 2024, 33 patients (33 eyes) diagnosed with IMH in Department of Ophthalmology of Changshu Second People’s Hospital were included in the study. Best corrected visual acuity (BCVA) and optical coherence tomography (OCT) examinations were performed on all affected eyes before surgery. BCVA examination was conducted using the international standard visual acuity chart, and the results were converted into the logarithm of the minimum angle of resolution (logMAR) visual acuity. The minimum diameter of the hole was measured using OCT. All affected eyes received standard 25G PPV treatment through the three channels of the flat part of the ciliary body. According to the surgical methods, they were divided into two groups: the OVD-assisted non-gas-dependent PPV combined with internal limiting membrane inversion and coverage treatment group (OVD group, 17 cases and 17 eyes) and the heavy water-assisted gas-dependent PPV combined with internal limiting membrane inversion and coverage treatment group (heavy water group, 16 cases and 16 eyes). Postoperatively, patients in the OVD group were not required to maintain a strict specific position, whereas those in the heavy water group needed to remain in a prone position for one week. The follow-up time points after the operation were 1 week, 1 month and 3 months. The main observation indicators included BCVA, intraocular pressure, hole closure rate and closure morphology of the two groups, as well as the occurrence of complications. The independent sample t test was used for comparison between groups. Pearson correlation analysis was used for the correlation between BCVA at 3 months after surgery and the minimum diameter of the surgical hole and BCVA before surgery. ResultsThree months after the operation, the rate of hole closure in the OVD group and the heavy water group was 17 (100.0%, 17/17) and 15 (93.8%, 15/16) eyes, respectively. There was no statistically significant difference in the hole closure rate (χ2=1.090) and closure type (Z=−0.780) between the two groups (P＞0.05). Compared with before the operation, the logMAR BCVA at each time point after the operation in the OVD group and the heavy water group was significantly improved (F=2.353, 1.375; P＜0.05). One week after the operation, the BCVA in the OVD group was significantly better than that in the heavy water group (t=-3.760, P＜0.01). In terms of intraocular pressure, compared with the baseline value before the surgery, there was a statistically significant difference in the OVD group one week after the surgery (Z=−3.454, P＜0.05). There were statistically significant differences in the heavy water group at 1 week, 1 month and 3 months after the operation (Z=−5.066, −3.423, −2.739; P＜0.05). After the operation, one eye in the heavy water group had high intraocular pressure, which returned to normal after combined treatment with intraocular pressure-lowering drugs. No ocular or systemic complications occurred in the OVD group. The results of the correlation analysis showed that postoperative BCVA was correlated with the minimum diameter of the surgical hole and BCVA before the surgery (r= 0.543, 0.658; P＜0.05). ConclusionsThe treatment of IMH with OVD-assisted non-gas-dependent PPV combined with internal limiting membrane flip coverage has a good effect. It helps promote the early recovery of macular morphology and visual function after surgery, and at the same time can avoid the maintenance of forced position and reduce perioperative risks.