The effects of cyclopentolate 1% versus tropicamide 1% on anterior segment angle parameters in three refractive pediatric groups

Abstract

Purpose This study aims to assess the effects of topical tropicamide 1% versus cyclopentolate hydrochloride 1% on the main numerical anterior chamber angle parameters using anterior segment optical coherence tomography (AS-OCT) in myopic, emmetropic, and hyperopic pediatric populations. Methods One hundred eight healthy and non-amblyopic children were enrolled in this prospective study. The children were assigned into three refractive groups of myopia, emmetropia, and hyperopia for both tropicamide and cyclopentolate administrations. Half of the children in three groups were instilled tropicamide 1%, and the remaining halves were instilled cyclopentolate hydrochloride 1%. AS-OCT measurements of the anterior chamber angle in three groups were performed at the temporal areas of the right eyes under similar conditions at baseline, 30 min after tropicamide, and 45 min after cyclopentolate instillations. Main measurements including the angle-opening distance at 500 mu m anterior to the scleral spur (AOD500), trabecular iris space area at 500 mu m anterior to the scleral spur (TISA500), and scleral spur angle (SSA) were compared between three refractive groups. Results The groups were age and gender-matched. The mean baseline spherical equivalents were similar in hyperopia groups of the tropicamide (+2.34 +/- 0.44) and cyclopentolate (+2.18 +/- 0.32) administrations (p = 0.284), as well as the myopic children administered with tropicamide (-2.68 +/- 0.40) and cyclopentolate (-2.74 +/- 0.38), (p = 0.406). All baseline measurements of AOD500, TISA500, and SSA measurements were similar in three refractive groups for both tropicamide and cyclopentolate as well as the final measurements and thus measurement changes between two sessions (P > 0.05 for all). Both drops induced an increase of AOD500, TISA500, and SSA measurements in three refractive groups (p < 0.05 for all). Conclusions Cycloplegic effects of topical instillations of tropicamide and cyclopentolate lead to a significant increase in anterior chamber angle measurements of AS-OCT. This similar effect of the drops should be considered for proper clinical assessment in children.