Air versus sulfur hexafluoride gas tamponade for small- and medium-sized macular holes in prone and non prone positions: a randomized controlled study

PURPOSE: To compare the anatomical and functional outcomes of patients with small- to medium-sized idiopathic macular holes (MHs) treated with air or sulfur hexafluoride (SF6) gas tamponade in prone and nonprone positions. METHODS: This was a multicentric randomized study of patients who were diagnosed with idiopathic small- to medium-sized (minimum linear diameter 250–400 μm) full-thickness macular holes and who underwent pars plana vitrectomy with inverted internal limiting membrane peeling. Patients were randomized into three groups: Group 1, air tamponade with prone positioning; Group 2, SF6 with prone positioning; and Group 3, SF6 without prone positioning. The primary outcomes assessed were the anatomical closure of MH and the type of MH closure. The secondary outcomes assessed were changes in best-corrected visual acuity (BCVA), postoperative changes on OCT and intraocular pressure (IOP). RESULTS: Eighty patients were enrolled in the study. The overall degree of anatomical closure was 92.5% (74/80). 88% (87.88% i.e. 21/22) in group-1, 100% (33/33) in Group-2 and 80% (20/25) in Group-3. The percentages of persistent MHs were 4.55% (1/22), 0% (0/33) and 20% (5/25) in groups 1, 2 and 3, respectively. The BCVA of patients improved from LogMAR 0.69 ± 0.29 to LogMAR 0.41 ± 0.29 at one month. BCVA improved across all groups postoperatively, with no significant differences at 1 month (p = 0.68) between all three groups. The photoreceptor (PR) layer defect length was greatest in the SF6 + non prone group (536.88 ± 341.1 microns), followed by the air + prone group (447.47 ± 346.35 microns) and least in the SF6 + prone group (272.5 ± 101.82 microns) at postoperative day 10. The PR layer defect was significantly lower in the SF6 + prone group and the air + prone group than in the SF6 + nonprone group (p = 0.049). IOP elevation occurred more frequently in the SF6 groups than in the air group (p = 0.015). CONCLUSION: Air tamponade is a viable alternative to SF6 for small to medium MHs in the prone position. It achieved comparable anatomical and functional outcomes while reducing IOP-related complications. Nonprone positioning, although convenient, results in a greater incidence of persistent holes, emphasizing the critical role of postoperative positioning even in small- and medium-sized MHs. TRIAL REGISTERED : The trial was registered with the clinical trial registry of India (CTRI/2023/05/067593);dated 19/05/2023