Purpose: We retrospectively analyzed 155 eyes of 155 patients who underwent trabeculectomy with and without antimetabolites to determine the time for recovery of visual acuity postoperatively and to determine factors associated with delayed recovery of visual acuity and visual loss.
Methods: Factors examined included age, race, preoperative visual field grading. Humphrey Field Analyzer's indices (mean deviation and corrected pattern standard deviation), optic nerve cup-to-disk ratio, antimetabolite use, postoperative complications, and postoperative hypotony. The mean age of the patient was 63.6 +/- 15.7 years. Mean follow-up was 14.4 +/- 8.5 months (range 6-30).
Results: One hundred forty-four patients (93%) regained their preoperative visual acuity, and 11 patients (7%) sustained visual loss. For the 144 patients who regained visual acuity, recovery time ranged between 1 and 244 days (median 6); recovery occurred before the second month in 128 patients (89%) and was delayed beyond 2 months in 16 patients (11%). Among the 60 primary open-angle glaucoma patients with preoperative visual acuity better than 20/200, those with delayed visual recovery had significantly worse preoperative visual field grades than did those with early recovery (p = 0.04). The preoperative Humphrey mean deviation was also higher (16.3 dB vs. 11.2 dB, p = 0.04). All 16 patients with delayed visual recovery also had postoperative hypotony (p = 0.01); this was transient (<2 weeks) in 12 patients and prolonged in four. In patients who failed to regain visual acuity, the visual loss did not correlate with any preoperative risk factors or hypotony, but these patients did have a higher incidence of postoperative complications (p = 0.05).
Conclusion: We conclude that patients with primary open-angle glaucoma who have advanced visual field defects are at greater risk of delayed visual recovery after trabeculectomy and that postoperative hypotony contributes to this delay.