Orthokeratology Linked WIth Reduced Axial Length Difference in Anisomyopia

Female optometrist checking vision of little girl with autorefractor
Side view portrait of friendly ophthalmologist using auto refractometer while examining child eyes. They looking at each and smiling
Clinicians may consider fitting orthokeratology lenses as a means of treating anisomyopia in children.

Orthokeratology (ortho-K) reduces interocular difference in axial length (AL) in children with anisomyopia, according to findings in Contact Lens and Anterior Eye.

Researchers conducted a randomized, controlled study to investigate the effects of overnight OK lens wear on the interocular AL difference in children with anisomyopia. The study included 60 children between the ages of 8 and 14 years. Participants were randomly assigned to an ortho-K group or control group who wore single-vision spectacles. AL was monitored at baseline and at 6 month intervals for 1 year. Axial elongation and interocular AL differences were compared between the groups. 

The more myopic eyes had similar axial elongation (0.36±0.17mm) to the less myopic eyes (0.37±0.17mm) in the control group at the 1-year follow-up (P >.05). The less myopic eyes exhibited significantly greater axial elongation (0.24±0.17mm) than the more myopic eyes (0.13±0.13mm) in the OK group at the 1-year follow-up (P <.05). Mean interocular AL difference decreased significantly in the ortho-K group in 1 year, from 0.47±0.24mm to 0.35±0.22mm (P <.05). Conversely, the mean interocular AL difference decreased slightly in the control group, from 0.56±0.28mm to 0.55±0.28mm (P >.05). 

Researchers observed a dose-response effect, in which AL increased as participants spent more time in OK lenses. According to investigators, “This result indicated that the greater the initial myopia, the lower the axial elongation when wearing OK lenses, which was the main reason why OK lenses could reduce the degree of anisomyopia.”

Study limitations include a relatively short follow-up period of 1 year, low initial values of myopia and anisomyopia, and the use of only 1 brand of OK lenses. 


Zhang Y, Sun X, Chen Y. Controlling anisomyopia in children by orthokeratology: A one-year randomised clinical trial. Cont Lens Anterior Eye. Published online November 13, 2021. doi.org/10.1016/j.clae.2021.101537