Effect of topical pressure-lowering medication on prevention of intraocular pressure spikes after intravitreal injection

Abstract

Purpose. The aim of this study was to evaluate pressure increases after intravitreal injections (IVI) and the interest in using prophylactic pressure-lowering medications. Methods. This was a prospective study of 250 anti-vascular endothelial growth factor IVI (ranibizumab) divided into 5 groups of 50 IVI (group 1: no intraocular pressure [IOP]-lowering medication; group 2: apraclonidine 1%; group 3: acetazolamide; group 4: fixed association brimonidine + timolol; group 5: fixed association dorzolamide + timolol). The IOP was measured before, immediately after (T1), 15 minutes after (T15), and 45 minutes after (T45) the IVI using a tonometer. The data were analyzed by analysis of variance followed by a Bonferroni as post hoc test if necessary. Results. The mean IOP peak in group 1 was 46.4±10 mmHg at T1, 21.7±10.2 mmHg at T15, and 15.4±8.6 mmHg at T45. It was not correlated with axial length (r=0.04, p=0.81) or lens status (phakic vs pseudophakic: p=0.88). A mild but significant correlation was found with age (r=0.36, p=0.006). Topical medications produced a significant reduction of IOP at every time point, of around 9 mmHg at T1. The reduction in IOP obtained with acetazolamide was not significant at T1 (-1.6 mmHg, p=0.12), but became significant at T15 and T45 (p=0.011 and p=0.015). Conclusions. Intraocular pressure spike was high but transient. Topical medications, however, produced a significant reduction in IOP spike as well as in the duration of the increased pressure. It would be advisable to prevent this IOP spike, especially when procedures are repeated, notably in patients with glaucoma.