Effects of Topical Timolol Maleate on Anterior Segment Structure, Pupil Dynamics and Retinal and Choroidal Thickness in Healthy Subjects

Abstract

Purpose: To investigate the effect of a single dose of topical timolol maleate 0.5% on anterior segment structure, pupil dynamics, and retinal and choroidal thickness in healthy subjects. Materials and Methods: Thirty subjects were included in this prospective and observational study.One eye of the participants received a single dose of topical benzalkonium chloride (BAC) preserved Timolol maleate 0.5% (Timosol 0.5%, Bilim Ilac, Istanbul, Turkey) (treated eye). Contralateral eye received a single dose of sodium hyaluronate ophthalmic solution without preservative (control eye). Main outcome measures were central corneal thickness (CCT), aqueous depth, anterior chamber volume, iridocorneal angle, horizontal anterior chamber diameter, static and dynamic pupil functions, central macular thickness, and choroidal thickness. Results: Mean CCT was signifi cantly higher after timolol instillation in treated eyes (p=0.001). Timolol did not affect aqueous depth, anterior chamber volume, iridocorneal angle and horizontal anterior chamber diameter in treated eyes (p>0.05 for each). Mean pupil diameters were similar under scotopic, mesopic and photopic conditions before and after timolol instillation (p>0.05 for each); however, pupil dilation speed was signifi cantly lower after timolol instillation in the treated eyes (p<0.05). Mean central macular thickness was signifi cantly higher after timolol instillation in treated eyes (p=0.005); however, no signifi cant difference was observed in choroidal thickness (p>0.05). Pre- and post-instillation outcomes were similar in control eyes for all parameters (p>0.05 for each). Conclusion: Topical BAC-preserved timolol maleate reduces pupil dilation speed without any effect on static pupil functions and increases the CCT and central macular thickness.