Posters

Outcome of primary phacotrabeculectomy with intraoperative Mitomycin C in primary open-angle and angle closure glaucoma in Singapore

Poster Details

First Author: D.Chen SINGAPORE

Co Author(s):    V. Koh   C. Sng   M. Aquino   T. Chew     

Abstract Details

Purpose:

Primary objective: - To determine the effect of primary phacotrabeculectomy with intraoperative Mitomycin C (MMC) on best corrected visual acuity (BCVA) and 1-year and 3-year success rates in Asian patients. Secondary objectives: - To determine any difference in BCVA outcome between primary open angle glaucoma (POAG) and primary angle-closure glaucoma (PACG). - To determine any difference in intraocular pressure (IOP) outcome, medications and success rates between POAG and PACG at 1 year and 3 years.

Setting:

The current study is part of a review of all eyes of patients who have undergone primary phacotrabeculectomy with intraoperative MMC at National University Hospital (NUH), Singapore, from November 1, 2001 to December 31, 2011. We retrospectively evaluated the case notes of 106 patients (153 eyes) with at least 3 years of follow-up after surgery.

Methods:

Patients with POAG or PACG who had undergone primary phacotrabeculectomy with MMC were included for analysis. For those who underwent bilateral operations, only the left eye was included. Primary angle closure was defined as more than two quadrants in which the posterior trabecular meshwork was not seen on indirect gonioscopy. Patient demographics, pre-operative history, use of anti-glaucoma therapy, BCVA, and IOPs measured through applanation tonometry before surgery were recorded in a standardized manner. Post-operatively, BCVA was collected at three months, while IOP and medication usage were collected at one day, one week, one month post-operatively, and then every three-monthly. Success was defined as IOP not below 6mmHg and not above stipulated upper limits (21mmHg, 18mmHg and 15mmHg respectively), further stratified into complete or qualified success based on medication usage. Statistical analysis was performed using SPSS statistical software version 21.0 (SPSS Inc, Chicago, Illinois). Differences between pre-operative and post-operative values were assessed using paired t-test or the sign test. Differences between groups were evaluated with independent t-test or non-parametric tests for continuous variables and with the χ2 test for categorical variables. P value of less than 0.05 was considered to be statistically significant.

Results:

A total of 54 subjects with POAG (mean age 68.8 +/- 8.3 years) and 44 subjects with PACG (mean age 65.7 +/- 8.2 years) were included. There was significant improvement in post-operative BCVA LogMAR (mean change of -0.0702; 95% CI: -0.037, -0.104, p<0.001). Patients with poorer pre-operative BCVA had a greater change in BCVA (p<0.001). One year (and three year)complete success rates for IOP less than 21, 18 and 15mmHg were 89.9% (79.7%), 88.6% (78.3%), and 73.4% (55.1%) respectively. There was a significant decrease from mean pre-op IOP at one year (-5.0 mmHg; 95%CI: 3.8 , 6.2; p<0.001) and three year post-operatively (-3.8 mmHg; 95% CI: 2.5, 5.2; p<0.001). There was a significant reduction in glaucoma medications after phaotrabeculectomy (-1.2 +/- 1.3; p<0.001). Patients who used two or more glaucoma medications pre-operatively had significantly higher IOP at one year post-operatively (p=0.036). Between POAG and PACG, there was no significant difference in post-operative BCVA (p=0.187). There was a trend showing a greater reduction in IOP for PACG than POAG at one year (PACG: -6.2 mmHg; POAG: -4.1 mmHg; p=0.074) and three year post-operatively (p=0.066). Reductions in glaucoma medications after surgery were similar for POAG and PACG (p=0.694).

Conclusions:

In Asian eyes, primary phacotrabeculectomy with intraoperative MMC appears to be an effective surgery in improving BCVA and reducing IOP up to three years, and reducing number of glaucoma medications post-operatively. The improvement in visual acuity were similar for POAG and PACG. There were greater reduction in IOP and better success rate for PACG than POAG, though the differences were not statistically significant. Currently, we are still collecting data from more patients to evaluate the differences in success rates between POAG and PACG in Asian eyes. FINANCIAL INTEREST: NONE