Sittikorn Laojaroenwanit, Vimontip Layanun, Pokpong Praneeprachachon, Parnchat Pukrushpan

We aimed to 1) determine the time of maximum cycloplegia after instillation of cyclopentolate 1% in children with brown irises, 2) evaluate the correlation between the pupillary reaction and time of maximum cycloplegia, and 3) identify any side effects of the medication. This was a prospective analytical study involving children aged 5 to 14 years who were attending refraction clinic. Cyclopentolate 1% was instilled three times at 10-minute intervals. The spherical equivalent, pupillary reaction, and pupillary diameter were recorded before the first drop and nine times after the last drop at 10-minute intervals. Side effects were assessed. Time of maximum cycloplegia was determined from the time point at which the 95% confidence interval of the differences between the mean spherical equivalent at each point and its final value at 110 minutes was reached and remained within the equivalence limit (±0.25 D). Sixty children were enrolled in this study. Their mean age was 9.8 years (range: 5-4 years). Time of maximum cycloplegia was reached at 30 minutes after the first instillation of cyclopentolate. A poor correlation was observed between the pupillary reaction and the time of maximum cycloplegia (r=-0.07). The mean pupillary diameter at 30 minutes was 3.7±1.3 mm, and further dilation occurred thereafter. No side effects were observed. In most children, maximum cycloplegia was reached 30 minutes after the first instillation of cyclopentolate. The absence of a pupillary reaction should not be used as an indicator of maximum cycloplegia.