Two Studies Examine Low-Concentration Atropine Eye Drops

Two separate studies published in peer-reviewed journals have reported findings on the use of low-concentration atropine eye drops, one examining long-term treatment in children with myopia and the other examining short-term physiological effects in healthy adults.

Childhood Myopia Trial

A clinical trial published in The BMJ assessed the effects of daily 0.01% atropine eye drops on myopia progression in children aged 6 to 12 years in the United Kingdom.

Study Parameters

• Participants: 289 children with myopia, average age 9.3 years (72% white ethnicity; 56% girls).
• Recruitment: Participants were recruited from five NHS hospital eye services and academic institutions between June 2019 and February 2022.
• Method: 192 children received 0.01% atropine drops, and 97 received a placebo for two years. All children wore standard spectacles.
• Final Data: Available for 230 children (151 atropine, 79 placebo).

Results

• Atropine treatment resulted in an average reduction of 0.38 diopters in refractive error.
• Axial length was reduced by an average of 0.14 mm compared to placebo.
• The atropine group showed a 0.36 mm greater pupil diameter.
• No significant differences in adverse events or tolerability measures (such as sore eyes, blurry vision, itchiness, or reading/writing difficulty) were observed between groups.

Limitations

Researchers noted limited generalizability outside trial settings and the potential influence of the COVID-19 pandemic during the study period.

The authors stated that low-concentration atropine eye drops could be a worthwhile addition to existing optical treatments for childhood myopia in the UK.

Short-Term Effects in Adults

A separate study, published in Eye and Vision and conducted by researchers at the University of Houston, examined the short-term effects of a single dose of low-concentration atropine.

Study Parameters

• Participants: 20 healthy adults.
• Method: A double-masked, randomized study where participants received a single instillation of either placebo or atropine (0.01%–0.1%) in the right eye across five separate sessions.
• Measurements: Eye structure, thickness, and axial length in the central retina were measured one hour and 24 hours after administration.

Results

• Changes in pupil size and focusing ability persisted for at least 24 hours.
• No short-term structural changes in axial length or retinal and choroidal thickness were observed.
• Temporary changes in retinal blood flow were noted, described as transient effects on superficial retinal perfusion in a time-dependent manner.

Context

Low-concentration atropine is commonly prescribed to slow myopia progression in children. This study aimed to clarify short-term retinal and choroidal effects, which were previously incompletely understood. Previous research by the same team (Professor Lisa Ostrin) had found similar effects on pupil size from a single drop of atropine.

The study is part of a broader research effort, including a $25 million NIH-funded clinical trial co-led by David Berntsen at the University of Houston, to delay myopia development in children.

Professor Lisa Ostrin stated: "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."

Ostrin added: "Characterizing these short-term effects is important for a better understanding of the physiological responses to atropine in clinical and research settings."