OrthoK Lenses Effect

Research Topic

An Investigation into the Correlation Between Myopia Patients’ Initial Treatment Ages and the Percent Improvement in Spherical Equivalence (%) after 1 Year of Wearing Orthokeratology Lenses, as Calculated by Spherical Power (diopter, D) and Cylinder Power (D).


In recent years, with myopia becoming a more and more common problem among children, many families choose OrthoK lenses treatment instead of traditional glasses.

In simple terms, SPH is the power of a lens, while CYL is the power of astigmatism (Mayo Clinic, 2019), they are considered direct measurements of one’s vision (Heiting, 2020). Another value, spherical equivalent (SE), as measured in diopters (D), is a comprehensive measurement of SPH and CYL, that is used to prescribe contact lenses to an individual with low astigmatism.

Raw data used in this investigation is publicly available on NCBI (Yin et al., 2019). Using the column of age, spherical diopter (SPH) and cylinder diopter (CYL), a new raw data table is generated. The initial, final and change in SE (D) and the percent and average percent improvement of SE (%) for each age group are calculated, respectively.

Using visual examination and Pearson’s correlation coefficient test, there is a weak positive correlation between patients’ initial treatment age and SE’s average percent improvement(%).