Subconjunctival Injections of Mitomycin C Are Associated with a Lower Incidence of Hypertensive Phase in Eyes with Ahmed Glaucoma Valve

Purpose: To evaluate the association of intraoperative and postoperative subconjunctival injections of mitomycin C (MMC) and rate of the hypertensive phase after implantation of the Ahmed glaucoma valve (AGV).

Design: Comparative case series.

Participants: This retrospective comparative study included 37 eyes of 35 patients with uncontrolled glaucoma on maximum tolerated medical therapy who underwent implantation of AGV by a single surgeon.

Methods: Consecutive cases operated without the use of MMC from 2015 to 2017 were compared with consecutive cases operated from 2018 to 2019 under a standardized protocol of subconjunctival MMC injections. The MMC group received 0.1 ml of MMC (0.25 mg/ml) injected intraoperatively, at 1 and 4 weeks after the surgery.

Main outcome measures: Incidence of the hypertensive phase (defined as intraocular pressure [IOP] >21 mmHg during the first 3 postoperative months) was compared across groups. Intraocular pressure and glaucoma medications were also compared during the course of the first 6 postoperative months.

Results: In the MMC and no-MMC groups, 17.6% (3/17) and 55.0% (11/20) of the cases exhibited a hypertensive phase (P = 0.04), respectively. Both groups were comparable in baseline characteristics, including age, preoperative IOP, preoperative glaucoma medications, and previous glaucoma surgeries. At 6 months, mean IOP was 14.0 ± 0.8 mmHg and 14.7 ± 0.9 mmHg for the MMC and no-MMC groups, respectively (P = 0.6). The mean number of glaucoma medications at 6 months was 1.2 ± 0.2 and 2.2 ± 0.3 in the MMC and no-MMC groups, respectively (P = 0.007).

Conclusions: Eyes that underwent implantation of AGV experienced a lower incidence of hypertensive phase and required fewer medications when using a standardized protocol of intraoperative and postoperative subconjunctival MMC injections.