Clinical experience with the Ahmed glaucoma valve implant in complicated glaucoma

To assess clinical outcomes of the Ahmed glaucoma valve implant, an aqueous shunting device with a unidirectional valve mechanism, in eyes with refractory glaucoma.

Consecutive patients with intractable glaucoma who underwent Ahmed glaucoma valve insertion were retrospectively reviewed. Only patients with a minimum of 6 months of follow-up were included. The presence of intraocular pressure (IOP) > or = 22 mmHg in the first 6 postoperative months was defined as a hypertensive phase (HP). This study included 19 eyes in 19 patients.

The mean preoperative IOP was 32.1 +/- 6.9 mmHg, with medication (mean times medication administered, 3.8 +/- 1.0; range, 0-3). The mean postoperative IOP was 7.8 +/- 2.2 mmHg on day 1, 11.3 +/- 4.4 mmHg at 1 week, 19.1 +/- 7.7 mm Hg at 1 month, 16.5 +/- 6.4 mmHg at 3 months, and 17.5 +/- 0.7 mmHg at 6 months, respectively. Twelve patients (63.2%) exhibited the HP. Nine patients (49.3%) experienced the HP at 1 month and 3 patients at 2 months after the operation. At the end of 6 months of follow-up, 11 patients (57.9%) who had exhibited the HP required additional anti-glaucoma medication to control the IOP (mean times medication was administered, 1.0 +/- 1.1; range, 0-2). Complications associated with the valve included hyphema in 1 case, choroidal effusion in 2 cases, iris plugging of the tube in 1 case, bleb encapsulation in 3 cases, and PK graft failure in 1 case. Postoperative hypotony resolved within 1 week.

The Ahmed glaucoma valve implant was safe and effective in this series. The hypertensive phase peaked in the first to second months after surgery.