A comparison of cycloplegic effect of cyclopentolate 0.5% versus 1.0% eye drops with five different refraction measurement modalities in young adults

Abstract

Purpose To compare the refraction before and after cycloplegia with 0.5% and 1.0% cyclopentolate eye drops using five different measurement modalities. Methods This prospective, clinical comparative study enrolled 96 eyes of 48 healthy patients with a mean age of 26.6 ± 4.21 years (range: 19–34). Subjective refraction, retinoscopy, and objective refraction were measured using three autorefractometers: Topcon KR-800 (TC), Retinomax K-plus 3 (RM + 3), and Retinomax K-plus Screeen (RM + S) under noncycloplegic and cycloplegic conditions. Cycloplegia was performed in the right eye using 0.5% and in the left eye with 1.0% cyclopentolate eye drops. Differences in refraction in noncycloplegia and cycloplegia, between cycloplegia with 0.5% and 1.0% cyclopentolate, and between the devices were investigated. Results Cycloplegic mean spherical equivalent was -1.77 ± 2.34 diopters (D) (-9.75 to + 1.625). All approaches showed a statistically significant hyperopic shift (p < 0.001, each) after induction of cycloplegia using both regimes. Lowest median (interquartile range) hyperopic shift was shown by TC (0.25 D (0.38)) and retinoscopy (0.25D (0.75)), and the highest by RM + 3 (0.75 (1.31)). No statistically significant differences between cycloplegia using 0.5% and 1.0% regimens were shown in all modalities (p > 0.05, each). In noncycloplegia, there were greater differences compared to cycloplegia. No influence of iris color on the refraction was found. Conclusion After induction of cycloplegia all devices showed a hyperopic shift and good comparability to retinoscopy. In all measurement modalities, no significant refraction differences between 0.5% and 1.0% cyclopentolate eye drops were seen. Therefore, 0.5% cyclopentolate was proven to have a sufficient effect with presumably better tolerability. Key messages What is known Cycloplegic refraction is a key test in the evaluation of any patient with active accommodation. The most frequently used clinical tests to determine the exact refraction are retinoscopy, subjective refraction, and objective refraction using autorefractometry. What is new No significant differences in the refraction between cycloplegia using 0.5% and 1.0% cyclopentolate eye drops were found. In noncycloplegia, hand-held autorefractometers tend to measure higher myopia. The evaluation of cycloplegic refraction showed good comparability between retinoscopy and subjective refraction as well as three different autorefractometers.