Purpose. To determine if there is a correlation between the outcome of trabeculectomy and the aqueous humor uric acid and ascorbic acid concentrations at the time of surgery. Methods. Aqueous humor samples were obtained from patients undergoing trabeculectomy and frozen at -80°C. Postoperatively all charts were reviewed and outcomes were defined as: 1) Unequivocal success-IOP reduced by >25% and ≤ 17 mmHg without medications with a minimum of 5 months follow-up (n=73). 2) Unequivocal failure-IOP ≥21 mmHg with reinstitution of medications within 3 months of surgery (n=26). 3) Other-All eyes that were not unequivocal successes or failures (n=400). The ascorbic acid and uric acid concentrations were determined in masked fashion by HPLC in those aqueous specimens from eyes with unequivocal outcomes. Results. The mean uric acid concentration was higher in the failure group (3.59 ± 1.44 mg%) than in the successful group (2.67 ± 1.50 mg%, p=0.008, two-tailed t test). Ascorbic acid levels were the same in the failure group (20.39 ± 10.22 mg%) and the successful group (23.59 ± 8.6 mg%, p=0.12). Other factors that correlated with failure were surgery located inferior (p=0.000) and male gender (p=0.015). No differences were found between the successes and failures with regard to age, race, or history of previous surgery. Conclusions. Uric acid concentrations were lower at the time of surgery in eyes that have successful outcomes than in those with unsuccessful outcomes. Uric acid is an indicator of free radicals in the aqueous humor that may predispose to surgical failure. No difference in ascorbic acid levels was detectable. Uric acid concentration becomes the first characteristic of aqueous humor composition that can be considered a risk factor for trabeculectomy failure.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Feb 15 1996|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience