Purpose: To determine the effect of oral acetazolamide on lowering the peak and duration of intraocular pressure (IOP) rise in glaucoma and glaucoma suspect patients, following intravitreal injection of ranibizumab for neovascular age-related macular degeneration.
Methods: The study was an open-label, parallel, randomised, controlled trial (EudraCT Number: 2010-023037-35). Twenty-four glaucoma or glaucoma suspect patients received either 500 mg acetazolamide or no treatment 60-90 min before 0.5 mg ranibizumab. The primary outcome measure was the difference in IOP immediately after injection (T0) and 5, 10, and 30 min following injection. ANCOVA was used to compare groups, adjusting for baseline IOP. The study was powered to detect a 9-mm Hg difference at T0.
Results: The IOP at T0 was 2.3 mm Hg higher in the non-treated group (mean 44.5 mm Hg, range (19-86 mm Hg)) compared with the treated group (mean 42.2 mm Hg, range (25-58 mm Hg)), but was not statistically significant after adjusting for baseline IOP (P=0.440). At 30 min, IOP was 4.9 mm Hg higher in the non-treated group (mean 20.6 mm Hg, range (11-46 mm Hg)) compared with the treated group (mean 15.7 mm Hg, range (8-21 mm Hg)). This was statistically significant after adjusting for baseline IOP (P=0.013).
Conclusions: Although the primary end points were not reached, 500 mg oral acetazolamide, 60-90 min before intravitreal injection, results in a statistically significant reduction in IOP at 3O min post injection. Prophylactic treatment may be considered as an option to minimise neuro-retinal rim damage in high-risk glaucoma patients who are most vulnerable to IOP spikes and undergoing repeated intravitreal injections of ranibizumab.