Clinical outcomes of combined versus separate carbachol and brimonidine drops in correcting presbyopia.

Almamoun Abdelkader,Herbert E. Kaufman

doi:10.1186/s40662-016-0065-3

Abstract

BackgroundTo test and compare in a masked fashion the efficacy of using a parasympathomimetic drug (3% carbachol) and an alpha-2 agonist (0.2% brimonidine) in both combined and separate forms to create optically beneficial miosis to pharmacologically improve vision in presbyopia.MethodsA prospective, double-masked, randomized, controlled clinical trial was conducted. Ten naturally emmetropic and presbyopic subjects between 42 and 58 years old with uncorrected distance visual acuity of at least 20/20 in both eyes without additional ocular pathology were eligible for inclusion. All subjects received 3% carbachol and 0.2% brimonidine in both combined and separate forms, 3% carbachol alone and 0.2% brimonidine (control) alone in their non-dominant eye in a crossover manner with one week washout between tests. The subjects’ pupil sizes and both near and distance visual acuities will be evaluated pre- and post-treatment at 1, 2, 4, and 8 h, by a masked examiner at the same room illumination.ResultsStatistically significant improvement in mean near visual acuity (NVA) was achieved in all subjects who received combined 3% carbachol and 0.2% brimonidine in the same formula compared with those who received separate forms or carbachol alone or brimonidine alone (P < 0.0001).ConclusionBased on the data, the combined solution demonstrated greater efficacy than the other solutions that were tested. Improving the depth of focus by making the pupil small caused statistically significant improvement in near visual acuity, with no change in binocular distance vision.Trial registration ACTRN12616001565437. Registered 11 November 2016.

Highlights

To test and compare in a masked fashion the efficacy of using a parasympathomimetic drug (3% carbachol) and an alpha-2 agonist (0.2% brimonidine) in both combined and separate forms to create optically beneficial miosis to pharmacologically improve vision in presbyopia
The KAMRA (AcuFocus, Irvine, California, USA) corneal inlay is an annular aperture inlaid in the cornea of one eye where a small entrance pupil is exploited to create a pinhole-type effect that increases the depth of focus and enables improvement in near visual acuity [11,12,13,14,15,16]
All subjects in our pilot study reported that they could drive safely day and night without distortions in the perception of any movement

Summary

Introduction

To test and compare in a masked fashion the efficacy of using a parasympathomimetic drug (3% carbachol) and an alpha-2 agonist (0.2% brimonidine) in both combined and separate forms to create optically beneficial miosis to pharmacologically improve vision in presbyopia. The KAMRA (AcuFocus, Irvine, California, USA) corneal inlay is an annular aperture inlaid in the cornea of one eye where a small entrance pupil is exploited to create a pinhole-type effect that increases the depth of focus and enables improvement in near visual acuity [11,12,13,14,15,16]. It reduces the amount of light entering the eye, so the interocular difference in retinal illuminance could alter perceived depth via the Pulfrich effect [17]. KAMRA subjects appeared to have adapted to the reduced illuminance in the treated eye

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Conclusion