Tropicamide has limited clinical effect on cycloplegia and mydriasis when combined with cyclopentolate and phenylephrine

Randomized Trial to Evaluate the Efficacy of the Nanodropper Device for Pupillary Dilation and Cycloplegia in Children

PURPOSE

We evaluated the noninferiority of 10.4 μl of eye drops eluted with a commercially available eye drop adapter, the Nanodropper (Nanodropper, Inc), on pupillary dilation and cycloplegia in children compared with the standard of care (SOC), 50 μl of eye drops.

DESIGN

Prospective randomized trial.

PARTICIPANTS

Pediatric patients scheduled for routine pupillary dilation at the University of California, San Francisco, at the Pediatric Ophthalmology Clinic were enrolled. Each participant provided 1 eye for the intervention group (Nanodropper) and 1 eye for the control group (SOC).

METHODS

Participants were randomized to receive small-volume dilating drops in 1 eye (Nanodropper) and SOC dilating drops in the other eye. Dilation was performed using 1 drop each of 1% cyclopentolate, 1% tropicamide, and 2.5% phenylephrine. Refraction and pupillometry were obtained before and 30 minutes after dilation. A noninferiority analysis was performed to assess change from before to after dilation in spherical equivalent and in pupil constriction percentage and maximum pupil diameter after dilation.

MAIN OUTCOME MEASURES

Spherical equivalent, maximum pupil diameter, and pupil constriction percentage.

RESULTS

One hundred eyes of 50 patients were included, with a mean ± standard deviation age of 9 ± 3 years. After controlling for baseline measurements, the spherical equivalent after dilation was 0.05 diopter (D) more (95% confidence interval [CI], -0.28 to 0.37 D) in the Nanodropper arm, which did not achieve noninferiority. Maximum pupil diameter after dilation was lower in the Nanodropper group (mean, -0.01 mm; 95% CI, -0.20 to -0.03), which did achieve noninferiority. Constriction percentage after dilation was 0.57 percentage points more (95% CI, -1.38 to 2.51 percentage points) in the Nanodropper group, which did not achieve noninferiority.

CONCLUSIONS

Administration of eye drops using a small-volume adapter demonstrated similar efficacy to SOC in a pediatric population. Strict noninferiority was met only for pupillary dilation and not for cycloplegia or constriction percentage; however, the small differences in the effect of the Nanodropper versus SOC on all primary outcomes were not clinically significant. We conclude that small-volume eye drops have the potential to decrease unnecessary medical waste and medication toxicity while maintaining therapeutic effect.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Pupillary Dilation in Research: More than Meets the Eye

Purpose: Pupil dilation is a commonly used procedure in vision research. While often considered a minimal risk procedure, there is the potential for significant adverse effects. Methods: Currently, there is variance in practices and protocols among researchers and institutions, perhaps due to a lack of guidelines for safe pupil dilation practices in research settings. In this perspective, we explore variables that can increase the potential for adverse effects and provide suggestions to limit their impact. Prior to dilation, an investigator can assess an individual's medical status and drug regimen when deciding upon a mydriatic agent to be used. Results: Assessing the angle through a variety of methods (i.e. penlight test, van Herick slit lamp, optical coherence tomography, gonioscopy) can also prevent inappropriate dilation of pupils with concerning anatomical features. During dilation, an investigator should look to limit the potential of infection and use caution in repeat dosing of dilation-resistant pupils. Conclusions: Post-dilation, an investigator should closely monitor eyes with elevated risk factors and improve an individual's health literacy on angle closure complications. When combined with proper informed consent processes regarding adverse effects, the aforementioned can allow for risk mitigation in studies using pupil dilation.