Factors Affecting Pupil Reactivity After Cycloplegia in Asian Children.

Purpose: The aim of this study was to evaluate the factors affecting cycloplegia, as determined by pupil reactivity, in Asian children.
Design: Prospective observational study.
Methods: Two-hundred sixty-eight children, aged 2 to 12 years, requiring cycloplegic refraction, were recruited. Nurses instilled 2 to 3 cycles of eye drops consisting of cyclopentolate 1%, tropicamide 0.5%, and phenylephrine 2.5%, and recorded the child's level of cooperation. Optometrists recorded pupil reactivity after the last cycle. Multivariate analysis determined factors affecting pupil reactivity including age, sex, race, number of eye drop cycles, pupil sizes before and after cycloplegia, and child's cooperation during eye drops instillation.
Results: The pupils in 36 children (13.4%) were found to be still reactive. On univariate analysis, children with reactive pupils also had smaller pupils after cycloplegia (6.27 ± 1.16 mm vs 7.42 ± 0.81 mm, P < 0.001). On multiple logistic regression analysis, for every 1-mm increase in the pupil size after cycloplegic eye drop administration, the odds of having reactive pupils decreases by 65% (odds ratio = 0.35, 95% confidence interval 0.25-0.51, P ≤ 0.001). Those who were uncooperative during administration of eye drops were 3.13 times more likely to have reactive pupils (95% confidence interval 1.21-8.13, P = 0.019), whereas age (P = 0.904), sex (P = 0.355), the number of cycles of eye drops (P = 0.462), and other psychological factors were not relevant in affecting pupil reactivity.
Conclusions: Pupil reactivity, which was used as a measure of cycloplegia, was more likely to be affected by children's level of cooperation during instillation of eye drops, rather than age and sex. Two cycles of eye drops were as effective as 3 cycles in producing cycloplegia.