Atropine with orthokeratology (AOK) treatment slows axial elongation more than using orthokeratology alone (OK) in children with myopia, according to a 2-year study published in Contact Lens and Anterior Eye

Researchers conducted a 2-year randomized clinical trial of 69 children with myopia (1.00 – 4.00 D, inclusive). They  randomly assigned participants to either an AOK (n=34, mean age 9.2±1.0 years, 20 girls) or OK group (n=35, 9.1±1.2 years, 19 girls). AOK treatment involved applying 0.01% atropine into each eye, 10 minutes prior to nightly 4-zone OK lens wear. The team measured axial length (the primary outcome), pupil size, and choroidal thickness at 1-month and at 6-month intervals until the 2-year study conclusion. 

Researchers observed slower axial elongation in the AOK group compared with the OK group over the course of the 2-year study duration (0.17±0.03 vs 0.34±0.03 mm; P <.001), revealing a difference of 0.18±.05 mm between the cohorts. They also noted larger increases in mesopic and photopic pupil size among children in the AOK cohort compared with the OK group (P =.003 and P <.001, respectively). Children in the AOK group also experienced greater choroidal thickening compared with OK group participants (difference 31.6±5.0 µm; P <.001).

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Slower axial elongation among AOK participants was associated with a larger increase in photopic pupil size and greater choroidal thickening, according to the report. 

“An additive effect was observed following combined treatment of 0.01% atropine and ortho-k, as axial elongation was slowed by 0.18 mm more with combined treatment of 0.01% atropine and ortho-k than with ortho-k alone over two years,” according to the researchers. “Slower axial elongation following 2-year AOK treatment may result from increased pupil dilation and a thickening in the choroid observed in the AOK group.”   

This study was limited by a high dropout rate (22%).

Disclosure: This research was supported by multiple sources. Please see the original reference for a full list of disclosures.   


Tan Q, Ng ALK, Cheng PMG, Woo VCP, Cho P. Combined 0.01% atropine with orthokeratology in childhood myopia control (AOK) study: a 2-year randomized clinical trial. Cont Lens Anterior Eye. Published online May 31, 2022. doi:10.1016/j.clae.2022.101723