Photo Credit: unoL

The following is a summary of “Effect of Eyedrop Size on Pupillary Dilation Using the Nanodropper Bottle Adapter,” published in the April 2025 issue of Clinical Ophthalmology by Chow et al. 

The Nanodropper, a commercially available eyedrop bottle adapter, produced 10 μL aliquots, addressing the limited absorption capacity of the conjunctival sac (7–10 μL) compared to the average 40 μL drop size from standard bottles.  

Researchers conducted a retrospective study to determine whether the Nanodropper provided a sufficient medication dose for mydriasis that was non-inferior to the standard eyedrop bottle.  

They assessed adults undergoing routine bilateral eye dilation, excluding those with anisocoria, prior mydriatic use, or unilateral pseudoexfoliation, 1 eye was randomly assigned to the Nanodropper, while the other received the standard bottle with a 50/50 mixture of 1% tropicamide and 2.5% phenylephrine. Pupil sizes were measured before and after dilation using a pupillometer and compared between eyes with a noninferiority margin of 0.5 mm.  

The results showed that 54 individuals (108 eyes, 54 pairs) were included. Pre-dilation pupil sizes were comparable between the Nanodropper and fellow eye. No significant difference was observed in post-dilation pupil size between eyes within the noninferiority margin of 0.5 mm (95% CI [−0.09, 0.15], P = 0.67).  

Investigators concluded that small-volume eye drops aided with the Nanodropper adapter were as effective as standard volume drops for mydriasis, potentially offering clinical, practical, and economic benefits by reducing medication waste, toxicity, and costs. 

Source: dovepress.com/the-effect-of-eyedrop-size-on-pupillary-dilation-using-the-nanodropper-peer-reviewed-fulltext-article-OPTH