Small-volume eye drop device matches standard of care in kids

A commercially available eye drop adapter device, dubbed the Nanodropper, results in comparable pupil diameter as standard of care (SOC) for routine pupillary dilation in paediatric patients, according to a recent study.

Fifty patients (mean age 9.12 years,58 percent men), contributing 100 eyes for analysis, were randomly allocated to the Nanodropper device or SOC, each with 50 eyes. Dilation was induced using a drop each of 1% cyclopentolate, 1% tropicamide, and 2.5% phenylephrine. Refraction and pupillometry analyses were performed before and 30 minutes after dilation.

At the postdilation assessment, pupil diameter increased by 1.95 mm (95 percent confidence interval [CI], 1.77–2.13) in the SOC group and by 1.77 mm (95 percent CI, 1.58–1.96) in the device group. [Ophthalmology 2022;doi:10.1016/j.ophtha.2022.10.016]

Primary statistical analysis revealed that the between-group mean difference of –0.01 mm (95 percent CI, –0.20 to –0.03) satisfied the noninferiority criteria at a margin of –0.20 mm. Noninferiority thresholds were determined by taking 10 percent of the SOC change score.

“We found a noninferior effect of small volume eye drops on the maximum pupil diameter,” the researchers said, pointing out that all assessed eyes saw a >6.0-mm pupil dilation.

“These findings add to the knowledge that as with adults and infants, small volume eye drops are similar to standard of care drops,” they added.

This effect remained true in subgroup analyses, suggesting that the Nanodropper device matched SOC regardless of refractive errors or iris colour.

Beyond clinical value

Nanodropper is a commercially available adapter device that delivers smaller volumes of eye drops. SOC, which uses eye dropper bottles, typically involves drops that are of 30–50 µL in volume, whereas the Nanodropper produces 10.4-µL drops. This is more in line with the limits of the human eye, which can only absorb 7–10 µL of fluid. [Surv Ophthalmol 1982;26:207-218]

However, whether a smaller solution volume will achieve worse or comparable efficacy to SOC remains unknown. “We hypothesize that small volume eyedrops will exhibit noninferior effects on pupillary dilation and cycloplegia as compared with the SOC,” the researchers said.

While the study did demonstrate comparable efficacies, the Nanodropper failed the noninferiority test in terms of several secondary outcomes. Postdilation constriction percentage increased by only 0.57 percentage points in the device group, which fell short of the 2.48-percent noninferiority margin.

Likewise, intraocular pressure was lower by 0.71 mm Hg in the Nanodropper than the SOC group, which did not meet the margin of –0.11 mm Hg.

Nevertheless, the researchers noted that these were of small clinical magnitude. Moreover, the benefits of smaller drops extend beyond clinical measures.

“Apart from efficacy, using smaller volume eye drops has economic and healthcare system advantages,” they said, pointing out that this could lead to fewer medical waste and less expensive care for patients and insurers.

“If equally effective to standard of care, small volume eye drops could result in cost savings to patients, healthcare providers, and the medical system,” they added.

Moving forward, more work needs to be done to understand further how small-volume eye drops impact care in ophthalmology clinics.

“Future studies could include an assessment of small volume eye drops in patients with pupillary abnormalities or an assessment of the effect of multiple administrations of small volume eye drops,” the researchers said.