Main port posterior lip depression versus intravenous mannitol to rescue acute intraoperative fluid misdirection syndrome

Abstract: PURPOSE: To compare the efficacy and safety of main port posterior lip depression (MPPLD) versus intravenous mannitol for intraocular pressure (IOP) reduction in acute intraoperative fluid misdirection syndrome (AIFMS) during cataract surgery. MATERIALS AND METHODS: This retrospective comparative study was conducted at a tertiary care center in Western India. Surgical records of cataract surgeries complicated by AIFMS between January 2022 and December 2024 were reviewed. A total of 82 patients were included, comprising the first consecutive 41 patients in each treatment group. AIFMS was defined as sudden shallowing of the anterior chamber with significant IOP elevation in the absence of choroidal hemorrhage. Outcomes assessed included time taken for IOP reduction, total surgical duration, postoperative corrected distance visual acuity (CDVA), and IOP, evaluated on postoperative day 1, day 7, and at 1 month. RESULTS: The incidence of AIFMS was 1.68% (108 of 6394 surgeries). MPPLD resulted in significantly faster IOP reduction compared to mannitol (45.93 ± 13.02 s vs. 29.71 ± 5.37 min, P < 0.01) and shorter surgical duration (50.54 ± 13.01 min vs. 77.63 ± 9.52 min, P < 0.01). On postoperative day 1, the MPPLD group demonstrated significantly lower IOP (17.66 ± 2.3 mmHg vs. 27.85 ± 3.1 mmHg, P < 0.01), reduced corneal edema as reflected by central corneal thickness (554.73 ± 9.71 µm vs. 570.05 ± 12.83 µm, P < 0.01), and superior CDVA ( P < 0.01). These differences persisted up to day 7 but were not significant at 1 month. CONCLUSION: Although infrequent, AIFMS presents a significant intraoperative challenge during routine cataract surgery, particularly for novice surgeons. MPPLD is a noninvasive, rapid, and effective alternative to intravenous mannitol, offering faster intraoperative resolution and improved early postoperative outcomes. This technique may be especially beneficial in resident training programs and resource-limited settings.