Prcis

Short-term overall success rates were high with either SGDD or CPC. However, SGDD was associated with more clinic visits and an increased risk of additional glaucoma surgery. Both treatments were reasonable options for eyes with inadequately controlled IOP after a single GDD.

Purpose

The purpose of this study is to compare the implantation of a second glaucoma drainage device (SGDD) and transscleral cyclophotocoagulation (CPC) in eyes with inadequately controlled intraocular pressure (IOP), despite the presence of a preexisting glaucoma drainage device.

Methods

Patients with inadequately controlled IOP, despite the medical therapy and a preexisting glaucoma drainage device, were enrolled at 14 clinical centers and randomly assigned to treatment with a SGDD or CPC.

Main outcome measures

Surgical failure was defined as: (1) IOP ≤5 mm Hg or >18 mm Hg or <20% reduction below baseline on maximum tolerated topical ocular hypotensive therapy, (2) reoperation for glaucoma, or (3) loss of light perception. The primary outcome measure was overall success with or without adjunctive medical therapy.

Results

Forty-two eyes of 42 participants were randomized to SGDD (n=22) or CPC (n=20). Mean duration of follow-up was 18.6 (±12.1; range: 1.1-38.6) months. The cumulative success rate was 79% for SGDD and 88% for CPC at 1 year ( P =0.63). Although the study was underpowered, no significant differences in IOP, postoperative number of IOP-lowering medications, or adverse events were observed. The number of additional glaucoma surgeries ( P =0.003), office visits during the first 3 months ( P <0.001), and office visits per month after month 3 ( P <0.001) were greater in the SGDD group.

Conclusions

Short-term overall success rates were high with either SGDD or CPC. However, SGDD was associated with more clinic visits and an increased risk of additional glaucoma surgery.