Measuring spherical equivalent refraction (SER) or cycloplegia level 20 or 30 minutes after cycloplegic drop instillation may produce similar results, according to a study published in Clinical and Experimental Optometry. These findings suggest that clinicians may be able to reduce wait times following drop instillation and more efficiently manage patient flow.
Researchers enrolled 99 children (age range, 12-13 years; 100% White) in the study and administered 0.5% proxymetacaine followed by 1.0% cyclopentolate to all participants. The cohort underwent SER measurements at 20- and 30-minutes post instillation while the research team analyzed data using paired t-testing, correlations, and linear regression.
There were no significant differences in cycloplegia levels at 20 and 30 minutes (0.438 vs 0.487 diopters [D]) post eyedrop instillation (t, 1.667, P = .099), according to the report. Analysis of agreement indices revealed good accuracy (0.999), precision (0.973), and concordance (0.972), and SER differed by 0.50 D or less at 20 and 30 minutes in 92% of eyes.
Refractive state did not create any differences in SER at 20 and 30 minutes, evidenced by mean difference values in patients with hyperopia (-.250 D), myopia (-0.049 D) and emmetropia (-0.033 D).
“[T]hese results suggest that it is possible to establish accurate refraction results 20-minutes instead of 30-minutes post-instillation of proxymetacaine hydrochloride 0.5% and cyclopentolate hydrochloride 1.0%,” according to the researchers. “This information is relevant to streamlining the delivery of pediatric and adolescent eyecare worldwide.”
Study limitations included failure to consider eye color and ethnic homogeneity, which may limit the globalization of these findings.
Doyle M, O’ Dwyer V, Harrington S. Comparison of cycloplegia at 20- and 30-minutes following proxymetacaine and cyclopentolate instillation in white 12-13-year-olds. Clin Exp Optom. Published online February 27, 2023. doi:10.1080/08164622.2023.2166398