Non-Cycloplegic Refractions Miscalculate Refractive Error Prevalence in Children

Non-cycloplegic refraction tends to overestimate myopia prevalence while underestimating hyperopia prevalence in pediatric populations, according to a study published in Ophthalmology.

Researchers performed both cycloplegic and non-cycloplegic refractions on 11,119 patients (mean age 10.8±4.0 years, 52.4% girls, 62.9% Black, 32.3% Hispanic) who visited a single center between September 2016 and June 2019. Individuals with poor visual acuity (non-cycloplegic autorefractions ±15 D spherical equivalent (SE) or cylinder >6D) or nystagmus were excluded.

Researchers noted that mean SE was higher for cycloplegic autorefraction compared with non-cycloplegic refraction (-0.23±2.31 D vs -0.87±2.11 D, 95% CI: 0.89-0.90), and non-cycloplegic autorefraction measured 0.65±1.04 D more myopic than cycloplegic autorefraction. Mean cylindrical refraction was 1.15±1.09 D in the non-cycloplegic group compared with 1.08±1.06 D in the cycloplegic group (mean difference 0.06±0.35 D). The regression slope (-0.18 between SE difference and cycloplegic autorefraction) decreased as age increased.

After adjusting for demographic factors and refractive error, the researchers found that those with a difference of 1.00 D or more SE between refractions (with non-cycloplegic refraction being more myopic) were more likely to be younger than 5 years (OR 1.45) and between 5 and 10 years of age (OR 1.32) compared with those aged 10 to less than 15 years. Children of Hispanic ethnicity (OR 1.23) were more likely to experience this myopic difference compared with students who were Black. Those with mild or moderate myopia were also more likely to experience it compared with individuals with hyperopia, and individuals with hyperopia were more likely to experience it compared with individuals with emmetropia.

“We found that three quarters of school-aged individuals undergoing autorefraction had less than 1D myopic SE difference between non-cycloplegic and cycloplegic refractions,” according to the investigators. “Non-cycloplegic refraction measurements were closest to cycloplegic refraction measurements in older children and in those with myopia.” These findings bring the role of using non-cycloplegic refraction on younger students at school-based vision programs into question.

Limitations of the study included its retrospective nature, a single center design, and the use of a hand-held autorefractor on some children.

Reference

Guo X, Shakarchi AF, Block SS, Friedman DS, Repka MX, Collins ME. Non-cycloplegic compared with cycloplegic refraction in a Chicago school-aged population. Ophthalmol. Published online February 28, 2022. doi:10.1016/j.ophtha.2022.02.027