Intermediate-term Results of a Randomized Clinical Trial of the 350- versus- the 500-mm² Baerveldt Implant

Background: The Baerveldt glaucoma implant is a large equatorial aqueous shunting device that is installed through a single-quadrant conjunctival incision. The intermediateterm results of a randomized study comparing the 350- and 500-mm² Baerveldt implants are reported. Methods: Seventy-three patients with medically uncontrollable, nonneovascular glaucomas associated with aphakia, pseudophakia, or failed filters were enrolled in a randomized, prospective study comparing 350- and 500-mm² Baerveldt implants. Surgical success was defined as 6 mmHg ≤ final intraocular pressure ≤ 21 mmHg without glaucoma reoperation or devastating complication. Results: Of patients with 350- and 500-mm² implants, 93% and 88%, respectively, achieved surgical success (18-month life-table analysis, P = 0.93). The 500-mm² implants afforded intraocular pressure control with significantly fewer medications (0.7 versus 1.3; P = 0.006). The postoperative visual acuities remained within one line of the preoperative visual acuities or improved in 62% and 66% of patients in the 350- and 500mm² groups, respectively (P = 0.93). Complication rates were statistically similar. The most frequent ones in the 350- and 500-mm² groups, respectively, were serous choroidal effusion (16% and 32%), strabismus (16% and 19%), anterior uveitis (14% and 11 %), and corneal or corneal graft edema (11 % each). Conclusion: The intermediate-term results of the 350- and 500-mm² Baerveldt implants were statistically comparable with respect to surgical and visual outcomes, as well as complications, although the larger implant was associated with a higher rate of some complications. However, the 500-mm² Baerveldt implant afforded intraocular pressure control with fewer medications than the 350-mm² implant.