Pars plana-modified Ahmed Glaucoma Valve for treatment of refractory glaucoma: a pilot study

Abstract

Purpose: This study was conducted to report the safety and efficacy of pars plana-modified Ahmed Glaucoma Valve PS2 in advanced secondary glaucoma.

Methods: We performed a prospective, interventional case series that included patients with advanced secondary glaucoma and uncontrolled intraocular pressure (IOP). Eleven eyes of nine patients with aphakic, neovascular, traumatic, inflammatory and pseudoexfoliation glaucoma were included. All patients had pars plana vitrectomy before tube insertion.

Results: One year after surgery, IOP was controlled (21 mmHg or less) in ten of 11 eyes (91%), seven (64%) did not need medical antiglaucoma therapy. Average IOP decreased from 32.2 +/- 8.3 mmHg before surgery to 15.7 +/- 7.7 mmHg postoperatively (P < 0.0001). The average number of topically used medications used decreased from 2.9 +/- 1.2 to 0.545 +/- 0.78 (P < 0.0001). Complications included transient hypotony (three eyes-two of them without tube ligature), transient choroidal effusion (three eyes) and an intermediate increase in IOP (seven eyes). Tube exchange was performed in one eye and needling/bleb excision in two patients.

Conclusions: Pars plana-modified Ahmed Valve implantation is effective and safe in advanced glaucoma. Partial ligature of the tube is necessary to prevent early hypotony. Close follow-up of patients is needed to monitor variations of IOP within the first year.