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

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

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.

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.

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.