Comparison of visual recovery following ex-PRESS versus trabeculectomy: results of a prospective randomized controlled trial

Abstract

Purpose: To compare the rate of visual recovery after Ex-PRESS implantation versus standard trabeculectomy.

Patients and methods: Subjects enrolled in a prospective randomized controlled trial comparing Ex-PRESS to trabeculectomy were analyzed for postoperative changes in visual acuity (VA). Risk factors for visual loss (split fixation, cup-disc ratio, intraocular pressure, visual field mean deviation, and hypotony) were evaluated.

Results: Sixty-four subjects were enrolled (33 Ex-PRESS, 31 trabeculectomy). There was no significant difference in mean logMAR VA between groups at baseline or any study visit. VA was significantly reduced up to week 2 following surgery in both the groups. However, by month 1, VA in the Ex-PRESS group was no longer significantly different from baseline (P=0.23) and remained nonsignificant at subsequent visits up to 6 months. In the trabeculectomy group, VA remained significantly lower than baseline at each study visit. At 6 months, 47% of the trabeculectomy eyes compared with 16% of the Ex-PRESS eyes had lost ≥2 Snellen lines (P=0.01). Reasons for VA loss included cataract, central retinal vein occlusion, and diabetic retinopathy, however, in a significant number of cases no cause could be determined. None of the risk factors evaluated were associated with vision loss.

Conclusions: Although there was no difference in mean VA between the Ex-PRESS and trabeculectomy groups at any time point, trabeculectomy eyes were more likely to lose ≥2 Snellen lines. In addition, VA recovered faster in the Ex-PRESS group.