A new paper that has been accepted for publication in Ophthalmic & Physiological Optics, the peer-reviewed journal of The College of Optometrists (UK), furthers understanding of myopia control efficacy in the context of normal childhood eye growth. Axial Length Targets for Myopia Control (Chamberlain P, et al.) is now available online via Open Access.
Since young eyes grow, even when not myopic, the paper compares axial elongation among children who remain emmetropic, children with untreated myopia progression, and children with myopia managed with CooperVision MiSight® 1 day myopia control contact lenses. The comparison uses data from the three-year MiSight® 1 day clinical study, the Orinda Longitudinal Study of Myopia (OLSM) and the Singapore Cohort Study of the Risk Factors for Myopia (SCORM).
The analysis revealed that the predicted three-year axial elongation for emmetropic children (0.24 mm) is similar to the mean three-year elongation in MiSight® 1 day-treated children with myopia (0.30 mm). In contrast, the axial elongation (0.63 mm) observed in the control group in the MiSight® 1 day clinical study was much higher, and similar to virtual cohorts based on the OLSM (0.70 mm) and SCORM (0.65 mm) models for myopia development.
This observation suggests that while abnormal myopic eye growth may be managed with MiSight® 1 day in age-appropriate children, normal, physiological eye growth may continue as the child ages. It supports the hypothesis that myopic axial elongation may be superimposed on underlying physiological axial elongation.
Some eye growth as part of the aging process is normal--myopic axial elongation is not. Our work further validates that evidence-based interventions can be highly effective in slowing that myopic eye growth. This offers hope to healthcare systems, currently bearing the growing burden of visual impairment linked to the increasing prevalence and severity of myopia."
Paul Chamberlain, BSc (Hons), MCOptom, Study Lead Author and Director of Research Programs for CooperVision
MiSight® 1 day contact lenses designed for myopia control have been shown to reduce the rate of axial elongation in children (aged 8-12 at the initiation of treatment) by 52% on average over a three-year period.†4 As measured by spherical refraction, the lens reduced the rate of myopia progression in age-appropriate children by 59% on average over the same period.
In assessing treatment effectiveness, we caution our industry away from applying arbitrary correction factors to account for normal, physiological eye growth until this has been better understood. Efficacy percentages may seem higher presented in that light, but it complicates understanding and valid comparisons," said co-author Mark Bullimore, MCOptom, PhD, FAAO. "Eye care professionals must be able to rely on the ever-growing body of myopia literature to make evidence-based clinical decisions."
Chamberlain, P., et al. (2021) Axial length targets for myopia control. Ophthalmic & Physiological Optics. doi.org/10.1111/opo.12812.