The recent AMIXT randomized controlled trial (RCT) focused on evaluating the efficacy of atropine, particularly low-dose concentrations, in managing myopia in children with intermittent exotropia. Low dose Atropine (LDA) has been increasingly studied as a treatment option to slow down the progression of myopia in children, including those with conditions like intermittent exotropia, which further complicates treatment.
To understand the efficacy of LDA, the primary outcome measured was change in cycloplegic spherical equivalent from baseline at 1 year. Secondary outcomes included change in axial length (AL), accommodative amplitude (AA), exotropia conditions, and binocular vision at 1 year.
Key Results
The AMIXT trial, along with other related studies, found that atropine at low concentrations (0.01% to 0.05%) significantly slowed the progression of myopia in children. Some key results from various studies include:
- Atropine 0.01% showed a reduction in myopia progression by approximately 0.3 to 0.5 dioptres (D) over two years, with fewer side effects compared to higher doses1.
- The LAMP study reported that 0.05% atropine was more effective than 0.01%, reducing myopia progression by 0.27 D over one year with minimal side effects2.
- In a five-year follow-up of atropine use in children, atropine 0.01% was associated with the lowest myopia progression and axial length changes, reinforcing its long-term efficacy3.
Efficacy and Safety
- Atropine 0.01% has become the standard due to its balance between efficacy and minimal side effects, such as reduced photophobia and accommodation loss. Other studies confirm similar findings in different populations, including European children, where myopia progression was slowed significantly4.
- In children with intermittent exotropia, the effects of atropine might extend beyond myopia control to improving binocular vision by stabilizing accommodation, a critical factor in exotropia management.
Comparative Studies and Cochrane Reviews
A Cochrane Review on atropine and other myopia control methods echoes these findings, suggesting that atropine, particularly at lower doses, is one of the most effective options for controlling myopia progression, with 0.01% being the preferred concentration due to its minimal side effects and significant efficacy5.
Another review did add the caveat that, whilst LDA and also Ortho-K were the most effective current therapies for myopia management, none of the therapies offered a large effect on slowing myopia progression to be genuinely considered as being highly effective.
Conclusion and Impact
The results of the AMIXT trial and similar studies affirm the role of low-dose atropine as a safe and effective treatment for managing myopia in children, including those with intermittent exotropia. Given the consistent findings on its ability to slow myopia progression, atropine may soon become the standard of care in paediatric myopia management in some countries, offering a low-risk intervention for a rapidly growing global health issue.
However, there are caveats around offering LDA in the UK, which are covered in another article.
References
Chia, A., Chua, W., Cheung, Y., Wong, W., Lingham, A., Fong, A., & Tan, D. (2012). Atropine for the treatment of childhood myopia: safety and efficacy of 0.5%, 0.1%, and 0.01% doses (Atropine for the Treatment of Myopia 2). Ophthalmology, 119 2, 347-54. https://doi.org/10.1016/j.ophtha.2011.07.031.
Yam, J., Jiang, Y., Tang, S., Law, A., Chan, J., Wong, E., Ko, S., Young, A., Tham, C., Chen, L., & Pang, C. (2019). Low-Concentration Atropine for Myopia Progression (LAMP) Study: A Randomized, Double-Blinded, Placebo-Controlled Trial of 0.05%, 0.025%, and 0.01% Atropine Eye Drops in Myopia Control. Ophthalmology, 126 1, 113-124. https://doi.org/10.1016/j.ophtha.2018.05.029.
Chia, A., Lu, Q., & Tan, D. (2016). Five-Year Clinical Trial on Atropine for the Treatment of Myopia 2: Myopia Control with Atropine 0.01% Eyedrops. Ophthalmology, 123 2, 391-9 . https://doi.org/10.1016/j.ophtha.2015.07.004.
Loughman, J., Kobia-Acquah, E., Lingham, G., Butler, J., Loskutova, E., Mackey, D., Lee, S., & Flitcroft, D. (2023). Myopia outcome study of atropine in children: Two-year result of daily 0.01% atropine in a European population. Acta ophthalmologica. https://doi.org/10.1111/aos.15761.
Wei, S., Li, S., An, W., Du, J., Liang, X., Sun, Y., Zhang, D., Tian, J., & Wang, N. (2020). Safety and Efficacy of Low-Dose Atropine Eyedrops for the Treatment of Myopia Progression in Chinese Children: A Randomized Clinical Trial. JAMA ophthalmology. https://doi.org/10.1001/jamaophthalmol.2020.3820.
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