Efficacy and Safety of 0.01%, 0.03%, and 0.05% Atropine Eye Drops in Reducing Myopia Progression: A Randomized Controlled Trial

Myopia is one of the fastest-growing ocular disorders worldwide and has become a major public health concern, especially among children and adolescents. Progressive myopia is clinically significant because it increases the lifetime risk of serious ocular complications such as retinal detachment, glaucoma, cataract, and myopic maculopathy. Even a small increase in refractive error has been shown to increase the risk of irreversible visual impairment, highlighting the need for effective strategies to slow myopia progression during childhood.

Atropine eye drops have emerged as one of the most effective pharmacological interventions for myopia control. Although high-dose atropine (1%) significantly slows myopia progression, its use is limited by adverse effects such as photophobia, blurred near vision, and poor tolerability. Recent landmark studies, including the Atropine for the Treatment of Myopia (ATOM) and Low-Concentration Atropine for Myopia Progression (LAMP) trials, demonstrated that lower concentrations of atropine (0.01%, 0.03%, and 0.05%) can effectively reduce myopia progression with fewer side effects. However, uncertainty remains regarding the optimal atropine concentration that provides the best balance between efficacy and safety, particularly in South Asian populations where local evidence is limited.

This study aims to compare the efficacy and safety of 0.01%, 0.03%, and 0.05% atropine eye drops in controlling myopia progression among children aged 6-18 years in Pakistan. The research question investigates whether these atropine concentrations differ in reducing myopia progression as measured by changes in spherical equivalent refraction (SER) and axial length (AL) over the study period.

The primary objective is to evaluate and compare the effectiveness of the three atropine concentrations in slowing myopia progression and to assess their safety profiles. The independent variable is the concentration of atropine eye drops, while the dependent variables include changes in SER and AL. Safety outcomes include the frequency and severity of ocular side effects such as photophobia, irritation, near blur, and pupillary dilatation, as well as systemic side effects including dry mouth, flushing, and tachycardia.

This prospective randomized open-label blinded endpoint (PROBE) trial will be conducted at the Department of Ophthalmology, Khyber Teaching Hospital, Peshawar, after approval from the Ethical Review Board of Khyber Medical College. The study duration will extend from June 2024 to December 2026. Written informed consent will be obtained from parents or guardians prior to enrollment.

Children aged 6-18 years with myopia ranging from -1.00 to -6.00 diopters will be recruited through pediatric ophthalmology and optometry outpatient services using consecutive non-probability sampling. Participants will undergo baseline ophthalmic assessment, including cycloplegic autorefraction, SER calculation, axial length measurement using Zeiss IOL Master, keratometry readings, best-corrected visual acuity assessment, and anterior and posterior segment examination. Demographic details such as age and gender will also be recorded.

Participants will be randomly allocated in a 1:1:1 ratio into three treatment groups using block randomization with allocation concealment. Group A will receive 0.01% atropine eye drops, Group B will receive 0.03% atropine, and Group C will receive 0.05% atropine, administered once daily at bedtime throughout the study period.

Follow-up visits will occur at baseline, 4 months, 8 months, 12 months, and 18 months. At each visit, SER, AL, keratometry readings, visual acuity, treatment adherence, and adverse events will be assessed. The primary outcomes will be changes in SER and axial length over 18 months, while secondary outcomes will include the frequency and type of ocular and systemic adverse effects associated with each atropine concentration.

Children with a history of ocular trauma or surgery, recent use of other myopia control interventions, or known atropine allergy will be excluded. The calculated sample size is 95 participants, distributed approximately equally among the three groups.

Statistical analysis will be performed using linear mixed-effects models to compare mean changes in SER and AL over time between groups while accounting for repeated measurements. Post hoc pairwise comparisons with Bonferroni correction will be applied when appropriate. Safety outcomes will be analyzed using chi-square or Fisher's exact tests. Multivariate regression analysis will also be performed to adjust for potential confounding variables such as age, baseline refractive error, axial length, and parental myopia.

This study is expected to provide locally relevant evidence regarding the most effective and safest low-dose atropine concentration for myopia control in Pakistani children and may contribute to future clinical guidelines for pediatric myopia management.