Primary glaucoma triple procedure with or without adjunctive mitomycin. Prognostic factors for filtration failure

The prerequisite for selective use of adjunctive mitomycin C (MMC) in primary glaucoma triple procedure (PGTP) is a better understanding of the prognostic factors. Therefore, the authors carried out the current study on the outcome of PGTP with and without adjunctive MMC to determine the prognostic factors for filtration failure of PGTP.

The study patients consisted of 174 consecutive primary open-angle glaucoma (POAG) patients undergoing PGTP. They were assigned randomly to either no adjunctive MMC (93 eyes of 93 patients) or adjunctive subconjunctival MMC (81 eyes of 81 patients) during the PGTP. After surgery, the patients were examined at regular intervals for visual acuity, intraocular pressure (IOP) control, medical therapy requirements, and complications. Filtration failure was determined according to two different criteria: (1) a less stringent set of criteria (criterion I) and (2) a more stringent set of criteria (criterion II).

There were no statistically significant differences between the groups with and without adjunctive MMC with respect to postoperative IOP, number of medications, and visual acuity outcome during mean follow-up (+/- standard deviation) of 25.1 +/- 5.5 months (P > 0.05 for each). However, there were prognostic factors for filtration failure in the control group but not in the MMC group. Black race, diabetes mellitus, preoperative IOP greater than or equal to 20 mmHg, and number of preoperative medications greater than two were found to be significant prognostic factors for filtration failure by criterion I. Black race, preoperative IOP greater than or equal to 20 mmHg and number of preoperative medications greater than 1 were significant prognostic factors for filtration failure by criterion II.

There was no statistically significant difference in the overall outcome of PGTP between control and MMC groups of nonselected patients with primary open-angle glaucoma. Black race, diabetes mellitus (by criterion I only), preoperative IOP greater than or equal to 20 mmHg, and number of preoperative medications greater than 2 (by criterion I) or greater than 1 (by criterion II) were found to be significant independent prognostic factors for filtration failure of PGTP without adjunctive MMC but no with adjunctive MMC. The use of adjunctive subconjunctival MMC in PGTP may have to be selective, primarily in those patients with primary open-angle glaucoma with one or more of the prognostic factors for filtration failure.