September 1, 2022
By Dwight Akerman, OD, MBA, FAAO, FBCLA, FIACLE
The aim of the atropine combined with orthokeratology (AOK) study was to explore whether there is an additive effect in retarding axial elongation if 0.01% atropine is used in conjunction with OrthoK over two years, employing OrthoK alone as a comparator.
A total of 96 Hong Kong Chinese children aged 6 to younger than 11 years with myopia (-1.00D to -4.00D, inclusive) were randomized into either the AOK or OK group in a 1:1 ratio. Axial length (the primary outcome) and secondary outcomes (e.g., pupil size and choroidal thickness) were measured at one-month and six-monthly intervals after commencement of treatment.
Intention-to-treat and per-protocol analyses showed significantly slower axial elongation in the AOK group than in the OK group over two years (P = 0.008, P < 0.001, respectively). AOK subjects had statistically slower axial elongation (adjusted mean [standard error], 0.17 [0.03] mm vs 0.34 [0.03] mm, P < 0.001), larger increase in mesopic (0.70 [0.09] mm vs 0.31 [0.09] mm, P = 0.003) and photopic pupil size (0.78 [0.07] mm vs 0.23 [0.07] mm, P < 0.001), and greater thickening of the choroid (22.6 [3.5] µm vs −9.0 [3.5] µm, P < 0.001) than OK subjects over two years. Except for a higher incidence of photophobia in the AOK group (P = 0.006), there were no differences in the incidence of any other symptom or adverse events between the two groups. Slower axial elongation was associated with a larger increase in the photopic pupil size and a greater thickening in the choroid in the AOK group.
The researchers concluded that an additive effect was observed following combined treatment of 0.01% atropine and OrthoK, as axial elongation was slowed by 0.18 mm more with combined treatment of 0.01% atropine and OrthoK than with OrthoK alone over two years. The combined treatment was well tolerated, with only a few reversible ocular adverse events and negligible side effects. The enlarged photopic pupil size and thickened choroid may contribute to the enhanced effectiveness of OrthoK and/or atropine for myopia control.
Abstract
Combined 0.01% Atropine with Orthokeratology in Childhood Myopia Control (AOK) Study: A 2-year Randomized Clinical Trial
Qi Tan, Alex Lk Ng, George Pm Cheng, Victor Cp Woo, Pauline Cho
Background: To investigate whether combining 0.01% atropine with orthokeratology (AOK) has a better effect in retarding axial elongation compared with orthokeratology alone (OK) over two years.
Methods: A total of 96 Chinese children aged six to < 11 years with myopia (1.00 – 4.00 D, inclusive) were randomized into either the AOK or OK group in a 1:1 ratio. Axial length (the primary outcome) and secondary outcomes (e.g., pupil size and choroidal thickness) were measured at 1-month and 6-monthly intervals after commencement of treatment.
Results: Both intention-to-treat and per-protocol analyses showed significantly slower axial elongation in the AOK group than in the OK group over two years (P = 0.008, P < 0.001, respectively). AOK subjects had statistically slower axial elongation (adjusted mean [standard error], 0.17 [0.03] mm vs 0.34 [0.03] mm, P < 0.001), larger increase in mesopic (0.70 [0.09] mm vs 0.31 [0.09] mm, P = 0.003) and photopic pupil size (0.78 [0.07] mm vs 0.23 [0.07] mm, P < 0.001), and greater thickening of the choroid (22.6 [3.5] µm vs −9.0 [3.5] µm, P < 0.001) than OK subjects over two years. Except for a higher incidence of photophobia in the AOK group (P = 0.006), there were no differences in the incidence of any other symptom or adverse events between the two groups. Slower axial elongation was associated with a larger increase in the photopic pupil size and a greater thickening in the choroid in the AOK group.
Conclusions: 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.
Tan, Q., Ng, A. L., Cheng, G. P., Woo, V. C., & Cho, P. (2022). Combined 0.01% atropine with orthokeratology in childhood myopia control (AOK) study: A 2-year randomized clinical trial. Contact Lens and Anterior Eye, 101723.
DOI: https://doi.org/10.1016/j.clae.2022.101723
