Comparison of Single Drop versus Two Drops 0.5% Tropicamide Using Manual and Automated Refraction in Children Aged 5-7 Years: A Randomized Controlled Trial

Background. Cycloplegia is important for obtaining accurate refractive measurements in children. However, the limited availability of cycloplegic agents in the Philippines presents challenges for pediatric mass-refraction programs.

Objective. This study evaluated the efficacy and reliability of 0.5% tropicamide administered as a single-drop versus the standard two-drop regimen for obtaining cycloplegic refraction in children.

Methods. This multicenter, randomized, single-sequence, crossover, controlled, single-blind study included children aged 5–7 years recruited from selected schools and a pediatric ophthalmology clinic in a tertiary hospital in the Philippines. Participants were randomized to receive a single drop and two drops of 0.5% tropicamide according to the study sequence. Automated refraction was performed at 5, 15, and 30 minutes, followed by manual refraction at 30–40 minutes. Another manual refraction performed 30-40 minutes after 2 drops of 0.5% tropicamide served as the reference standard. The pediatric ophthalmologists performing the reference refraction were masked to the automated refraction results.

Results. A total of 219 eyes from 111 children were included, 59% (66/111) of whom were male. Hyperopia was the most common refractive error (76%, 166/219), followed by astigmatism (62.6%, 137/219) and myopia (16%, 34/219). After a single drop of tropicamide, auto-mated refraction at 5, 15, and 30 minutes demonstrated significant differences from the reference standard in spherical equivalent (SE), sphere, cylinder, and axis (all P <0.05). The median SE values at 5, 15, and 30 minutes were 0.25 D (Interquartile Range or IQR, 1.25 D), 0.25 D (IQR, 1.50 D), and 0.375 D (IQR, 1.50 D), respectively, compared with 0.75 D (IQR, 1.75 D) for the reference refraction. In contrast, manual refraction performed 30–40 minutes after a single drop did not differ significantly from the reference standard for sphere (P = 0.479), cylinder (P = 0.470), axis (P = 0.137), or SE (P = 0.327). Following two drops, automated refraction at all time points remained significantly different from the reference standard for cylinder, axis, and SE. However, at 30 minutes, the spherical refraction did not differ significantly from the reference standard (P = 0.209).

Conclusion. In children aged 5–7 years, manual refraction performed 30–40 minutes after either a single- or two-drop administration of 0.5% tropicamide produced results comparable with the reference standard. Automated refraction following a single drop demonstrated greater variability and should be interpreted with caution. For mass-refraction settings, a single-drop regimen followed by manual refraction after 30–40 minutes may be a practical alternative to the standard two-drop regimen. When automated refraction is used, the sphere obtained after two drops may provide an estimate of cycloplegic refraction.