Single low-dose atropine drop shows daylong effects for myopia

Groundbreaking research from the University of Houston shows that a single low-dose atropine eye drop can produce daylong effects in managing myopia, or nearsightedness, which affects roughly one-third of U.S. adults.

Professor of Optometry Lisa Ostrin and postdoctoral researcher Barsha Lal are reporting that even one drop in the eye of low-dose atropine (0.01%–0.1%) produces clear changes in pupil size and focusing ability that persist for at least 24 hours. Importantly, they also found that the drop shows no short-term structural effects on the eye, with only temporary changes in blood flow inside the retina. 

Ostrin's latest research is published in the journal Eye and Vision. It adds to a growing body of vision research from David Berntsen, Golden-Golden Professor of Optometry at the University of Houston, who is co-leading a national $25 million NIH-funded clinical trial to delay the development of myopia in children by using the atropine drops. 

Low concentration atropine is widely prescribed to slow myopia progression in children, yet its short-term retinal and choroidal effects remain incompletely understood. Ostrin's new study evaluated short-term effects of a range of low atropine concentrations on the length of the eye, the blood vessels in the retina and the thickness of the retina and choroid, which sits just behind the retina. These are important measurements because longer eye length is associated with myopia and as it gets longer, the retina and choroid are stretched. 

"These findings indicate that a single instillation of atropine does not alter axial length or retinal or choroidal thickness over 24 hours but may transiently affect superficial retinal perfusion in a time-dependent manner," said Ostrin. 

In the double-masked, randomized study, twenty healthy adults received a single instillation of either a placebo or atropine in the right eye during five separate sessions. Researchers then checked the eye structure, thickness, and length in the central retina both one-hour and 24-hours later. 

"Characterizing these short-term effects is important for a better understanding of the physiological responses to atropine in clinical and research settings," said Ostrin who previously published research results of a study investigating the short-term effects of a range of low-dose atropine concentrations on the pupils of young adults. In that study, she found similar results with a single drop of atropine inducing significant changes in the pupils. 

Together, the studies indicate that atropine induces early functional and vascular effects in the eye, in the absence of structural change. 

"By linking objective ocular responses with subjective visual experience, this work advances our understanding of how atropine works and supports more precise, evidence-based, and individualized approaches to myopia management," said Ostrin.