Ocular hypotony after laser suture lysis following trabeculectomy with mitomycin C

Background: To report our experience with laser suture lysis (LSL) followin g trabeculectomy with mitomycin C, its timing, effectiveness and related co mplications. Methods: We retrospectively examined 38 consecutive eyes of 36 patients that underwent LSL following trabeculectomy with mitomycin C. Res ults: The mean preLSL intraocular pressure (IOP) was 27.0 mm Hg (SD 6.3, ra nge 16-39 mm Hg) and the postLSL IOP (IOP 1 h after the last session of LSL ) was 16.0 mm Hg (SD 7.2, range 3-31 mm Hg). Following the LSL in 7 eyes (7 of 38) hypotony (IOP<6 mm Hg, lasting more than 24 h) developed. Two group s were defined. In group I no hypotony was found after LSL and group II wen t through a period of hypotony. The time interval between surgery and LSL w as significantly shorter in group II (mean 5.7, SD 7.5, range 1-19 days), c ompared to group I (mean 14.7, SD 13.0, range 1-44 days) (p=0.041). The mea n final IOP (IOP measured at the last visit) was 13.3 mm Hg (SD 3.4, range 6-20 mm Hg) and mean follow-up was 6.1 months (SD 3.9, range 2.0-15.2 month s). No hypotony was found at final examination. PostLSL IOP and final IOP w ere significantly lower in group II (p=0.002 and p=0.024 respectively). IOP reduction by LSL was significantly greater in group II (p=0.046). Conclusi on: LSL is an effective and safe procedure to lower the IOP following trabe culectomy with mitomycin C. Early application of LSL results in lower final IOPs, but has a higher risk of hypotony.