Researchers offer a new approach to search for the possible mechanisms leading to effective myopic control. They developed a model that integrates the effects of mean spherical equivalent, corneal asymmetry and corneal astigmatism into a calculation of the relative corneal refractive power spatial distribution. The model yields a single metric—maximal relative corneal refractive power (mRCRP)—which could be used to quantify the probability of achieving an effective control of myopic progression via a logistic regression-based analysis.

To demonstrate that a clear myopic control effect is potentially related to a larger modulation of mRCRP, 55 children between eight and 12 years old participated in a study where axial growth was calculated before and one year after orthokeratology. A total of 45 subjects achieved effective control, but for 10 the treatment was ineffective. Modulations of mRCRP were significantly larger in the effective than in the ineffective group (1.17D vs. 0.64D for corneal asymmetry; 0.85D vs. 0.35D for astigmatism). The mean refractive power values did not differ between the groups. With a peak mRCRP greater than 4.5D, a subject had an above 80% chance to achieve effective myopia control.

Researchers hope their model enables clinicians to estimate myopia outcomes early and provides new insights to lens design.

Wang J, Yang D, Bi H, et al. A new method to analyze the relative corneal refractive power and its association to myopic progression control with orthokeratology. Trans Vis Sci Tech. 2018;7(6):17.