Laser suture lysis after trabeculectomy

The author attempted to avoid ocular hypotony following a mitomycin-C trabeculectomy by controlling the interval between surgery and laser suture lysis.

When 10 seconds of digital pressure on the eye following a mitomycin-C trabeculectomy produced a 20% drop of the intraocular pressure, the decision of whether or not to perform laser suture lysis was delayed until the following examination.

Twenty-nine consecutive eyes (27 patients) with primary open-angle glaucoma underwent mitomycin-C trabeculectomy in which laser suture lysis was required during the postoperative period to reach the target intraocular pressure. The eyes were classified by the severity of the glaucoma: mild, moderate, and severe. For moderate and severe glaucoma, an unqualified success was defined as an intraocular pressure of 10 +/- 2 mm Hg. A qualified success had an intraocular pressure of 5 to 7 mm Hg or 13 to 15 mm Hg. Failure was defined as an intraocular pressure less than 5 mm Hg or greater than 15 mm Hg. Fifteen eyes were called success, 7 eyes qualified success, and 7 eyes failure. When the final laser suture lysis was carried out within the first two postoperative months, two of the failure eyes sustained hypotony. If the final laser suture lysis had been carried out after the first two postoperative months, there were no eyes with hypotony. There was no statistical difference in the final intraocular pressure between the early laser suture lysis and late laser suture lysis groups.

From this pilot study it would appear that delaying the final laser suture lysis following trabeculectomy (MMC) until after the second postoperative month may reduce the risk of hypotony without adversely affecting the final intraocular pressure.