Cycloplegic Refraction Outcomes at 30 Minutes Versus 3 Hours After Cyclopentolate 1% in Children: A Prospective Within-Subject Study
DOI:
https://doi.org/10.66021/pakmcr1820Keywords:
Cycloplegic Refraction; Cyclopentolate; Accommodation; Refractive Error; Spherical Equivalent; Iris Pigmentation; Paediatric Eye CareAbstract
Background: Cycloplegic refraction is the reference method for assessing refractive error in children, and cyclopentolate 1% is widely used. Waiting times vary from 30 minutes to several hours, and evidence comparing a short and a long interval within the same children is limited, particularly in South Asian populations.
Objective: To compare cycloplegic refraction at 30 minutes and 3 hours after cyclopentolate 1% in children aged 4–11 years.
Methods: In this prospective, within-subject study at a private optical practice in Lahore, Pakistan, 60 children were enrolled by consecutive sampling. Each child had baseline visual acuity and non-cycloplegic refraction, then received cyclopentolate 1% in both eyes. Sphere, cylinder, axis, spherical equivalent (SE), visual acuity and adverse effects were recorded at 30 minutes and 3 hours. Paired t-tests, Bland–Altman analysis, McNemar's test and pre-specified subgroup analyses (iris pigmentation, age band) were used. Significance was set at p < 0.05.
Results: Fifty-six children (93.3%) completed both assessments. Mean SE was 1.52 ± 0.61 D at 30 minutes and 1.56 ± 0.60 D at 3 hours (mean difference 0.04 D, 95% CI −0.04 to 0.12, p = .34). Cylinder, axis and visual acuity also did not differ significantly. Bland–Altman 95% limits of agreement were −0.65 to 0.57 D. Children with dark irides (n = 17) showed a significant increase in hyperopic SE at 3 hours (1.60 to 1.87 D; mean difference 0.27 D, 95% CI 0.003 to 0.537, p = .048); light (n = 14) and medium (n = 25) irides did not. No age band showed a significant change. Adverse effects were similar at both time points.
Conclusion: For most children, a 30-minute wait gives refractive values equivalent to a 3-hour wait. Children with dark irides may be under-corrected for hyperopia at 30 minutes, which supports a risk-stratified protocol with an extended wait or confirmatory re-check for this group. The dark-iris finding is based on a small subgroup and should be confirmed in larger studies.
