Predictive value of early IOP in mitomycin-C augmented trabeculectomy

To determine whether early intraocular pressure (IOP) after mitomycin-C (MMC) augmented trabeculectomy has any predictive value for intermediate IOP outcome.

Retrospective case note review. All cases of trabeculectomy using MMC augmentation and at least 1-year follow-up during the study period were included. Cases where a bleb leak occurred were excluded from the analysis. Only first eyes operated upon during the study period were included. Patient demographics and postoperative course were documented and analyzed. Early IOP measurements at day 1, day 7, and month 1 postoperatively were correlated to IOP at 1 year or final follow-up.

One hundred nineteen trabeculectomies were identified. Of these 27 (22.7%) had an early bleb leak and were excluded. Further analysis was carried out on the remaining 92 cases. Mean age of cases was 70.8 years. Nine cases (9.8%) were repeat trabeculectomies. Mean follow-up time was 18.5 months (range 12 to 60 mo). Patients with a final IOP of < or =16 mm Hg (without drops or further surgery) (unqualified successes) had a mean day 1 IOP of 12.5 mm Hg compared with 17.4 mm Hg in those with an IOP more than 16 mm Hg at final follow-up (P=0.02). Patients with a final IOP of < or =16 mm Hg (with or without drops) (qualified successes) had mean day 1 IOP of 13.3 mm Hg compared with 17.1 mm Hg in those with an IOP of >16 mm Hg at final follow-up (P=0.06). At 1 month the mean IOPs were 10.7 mm Hg and 19.5 mm Hg, respectively (P<0.001). By logistic regression analysis at final recorded visit those cases in the lowest IOP quartile at 1 month were 14 times more likely to have an IOP < or =16 mm Hg without treatment than those in the highest quartile at 1 month.

Our data suggests that a low early postoperative IOP measurement is a predictive factor for IOP value and success after intermediate length follow-up in patients undergoing trabeculectomy surgery augmented with MMC.