A randomized clinical trial using cyclopentolate and tropicamide to compare cycloplegic refraction in Chinese young adults with dark irises

Abstract

Background To evaluate the necessity of cycloplegia for epidemiological studies of refraction in Chinese young adults (aged 17–22 years) with dark irises, and to compare the cycloplegic effects of 1% cyclopentolate and 0.5% tropicamide in them. Methods A total of 300 young adults (108 males and 192 females) aged 17 to 22 years (mean 19.03 ± 1.01) were recruited from Tianjin Medical University from November 2019 to January 2020. Participants were randomly divided into two groups. In the cyclopentolate group, two drops of 1% cyclopentolate eye drop were administrated (one drop every 5 min), followed by autorefraction and subjective refraction 30 to 45 min later. In the tropicamide group, four drops of 1% Mydrin P (Tropicamide 0.5%, phenylephrine HCl 0.5%) eye drop were given (one drop every 5 min), followed by autorefraction and subjective refraction 20 to 30 min later. The participants and the examiners were masked to the medication. Distance visual acuity, intraocular pressure (IOP), non-cycloplegic and cycloplegic autorefraction (Topcon KR-800, Topcon Co. Tokyo, Japan), non-cycloplegic and cycloplegic subjective refraction and ocular biometry (Lenstar LS-900) were performed. Results The values of spherical equivalent (SE) and sphere component were significantly different before and after cycloplegia in the cyclopentolate group and the tropicamide group (p < 0.05). The mean difference between noncycloplegic and cycloplegic autorefraction SE was 0.39 D (±0.66 D) in the cyclopentolate group and 0.39 D (±0.34 D) in the tropicamide group. There was no significant difference in the change of SE and sphere component after cycloplegia between the cyclopentolate group and the tropicamide group (p > 0.05). In each group, no significant difference was found between autorefraction and subjective refraction after cycloplegia (p > 0.05). We also found that more positive or less negative cycloplegic refraction was associated with the higher difference in SE in each group. Conclusions Cycloplegic refractions were generally more positive or less negative than non-cycloplegic refractions. It is necessary to perform cycloplegia for Chinese young adults with dark irises to obtain accurate refractive errors. We suggest that cycloplegic autorefraction using tropicamide may be considered as a reliable method for epidemiological studies of refraction in Chinese young adults with dark irises. Trial registration The study was registered on September 7, 2019 (Registration number: ChiCTR1900025774).

The Reliability and Acceptability of RDx-Based Tele-Controlled Subjective Refraction Compared with Traditional Subjective Refraction

“…This was also the first time anyone has deeply investigated the participants’ attitudes toward tele-controlled subjective refraction. In our cross-sectional study, we found no statistically significant differences between traditional subjective refraction and tele-controlled subjective refraction for any parameters, and the 95% limits of agreement between the 2 methods of refraction in the S (±0.42 D), C (±0.39 D), and SE (±0.36 D) were both similar to a previous study on reproducibility of subjective refraction (±0.44 D 16 for S, ±0.31 D 17 for C, and ±0.37 D to ±0.56 D 18 – 21 for SE). Researchers generally agree that the variation of refractive error should be at least ±0.50 D and consider this to be the minimum significant shift in a refractive state.…”

“…First, all subjective refraction was conducted without cycloplegia. As observed by Pei et al, 17 cycloplegic measurements are generally more positive or less negative than refractions without cycloplegia. Although enough fogging and standardized operations were performed to minimize the influences induced by accommodation, 31 this may not be enough for individuals with hyperopia or under the age of 10 years.…”

Relationship between axial length and spherical equivalent refraction in Chinese children

“…For other children, cycloplegia in our study was obtained by tropicamide instead, considering some children's photophobia and rejections from parents. However, as a recent prospective observational study shows similar effects in producing cycloplegia using tropicamide and cyclopentolate in Chinese young people, 31 the SER of children who received tropicamide may be overestimated. Thirdly, previous studies indicated that axial elongation usually occurred concurrently with loss of lens power in children.…”

Effect of low‐dose atropine (0.01%) on crystalline lens power among school‐aged children with progressive myopia

“…At baseline, cycloplegic autorefraction was performed 30 min after three instillations of tropicamide 1% drops, 5 min apart. 10 Care was taken to see that the pupils were dilated to at least 6 mm and that no pupillary reflex was present post dilatation. Automated refraction was measured using the Nidek ARK-1 autorefractor (nidek -intl.com).…”