Atropine and orthokeratology combo effective for control of childhood myopia, study finds

China: Combined treatment of 0.01% atropine and ortho-k slowed axial elongation by 0.18 mm more than that with ortho-k alone over two years in children with myopia, states a study report published in Contact Lens and Anterior Eye. 

The global prevalence of myopia is increasing at alarming rates, especially in adolescents aged 16 to 18 years. A range of optical and pharmacological interventions have been investigated to limit childhood myopia progression. The use of atropine is effective but is associated with significant side effects during treatment and a strong rebound effect after discontinuation. Of the optical interventions for myopia control, orthokeratology (ortho-k) was ranked as the most effective in reducing axial elongation compared to wearing single-vision spectacles or soft contact lenses. Combination therapy (1% atropine and ortho-k) has been suggested as an approach to improve treatment efficacy in retarding axial elongation.

Qi Tan, The Hong Kong Polytechnic University, China, and colleagues conducted a 2-year randomized trial to investigate whether combining 0.01% atropine with ortho-k (AOK) has a better effect in retarding axial elongation, compared with ortho-k alone (OK) over two years.

Researchers randomized a total of 96 Chinese children aged six to < 11 years with myopia (1.00 – 4.00 D, inclusive) into either the AOK or OK group in a 1:1 ratio for the study. The AOK group was treated with instillation of one drop of preservative-free 0.01% atropine into each eye, 10 min before nightly wear of 4-zone ortho-k lenses while subjects in the OK group only wore ortho-k lenses nightly. 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.

Key findings of the study,

• There was significantly slower axial elongation in the AOK group than the OK group over two years. 

• AOK subjects had a statistically larger increase in mesopic and photopic pupil size and greater thickening of the choroid than OK subjects

• Except for a higher incidence of photophobia in the AOK group, there were no differences in the incidence of any other symptom or adverse events between the two groups.

The authors concluded that axial elongation was slowed by 0.18 mm more with combined treatment than with ortho-k alone over two years. Enlarged photopic pupil size and greater choroidal thickening in patients in the combined treatment group may be contributory to the enhanced effectiveness of the combined treatment.

The combined treatment showed an additive effect and was well-tolerated by children with myopia. Further studies are indicated to explain the mechanism of this additive effect, the authors wrote.

Reference:

Qi Tan, Alex LK Ng, George PM Cheng, Victor CP Woo, Pauline Cho Open Access Published:May 31, 2022DOI:https://doi.org/10.1016/j.clae.2022.101723