Evaluation of Orthokeratology Lens Fitting Assisted by Sagittal Height Simulation Software

To evaluate a novel sagittal height fitting algorithm for estimation of alignment curve (AC) radius during Euclid orthokeratology lens trial.

Chinese myopic children were recruited in this study and were randomly divided into two groups. The AC radius of one group was calculated by the novel fitting algorithm. The AC radius of the other group was decided by the optometrist using flat K readings and eccentricity values. The number of lens trials was recorded for each patient, and the consistencies of AC radius between the first trial lenses and the final ordered lenses were tested by Pearson correlations and Bland-Altman plots.

One hundred three adolescent patients (103 eyes) were enrolled, including 57 boys and 46 girls. The numbers of trials for the novel algorithm and traditional method were 1.2±0.4 times versus 1.4±0.5 times, respectively, and the difference between the two methods was significant (t=2.404, P=0.018). The difference of AC value between the first trial lens and the lens to be produced for the novel algorithm and traditional method 0.000±0.020 mm and 0.003±0.028 mm separately. There was no statistical difference between the two methods (t=0.748, P=0.456).

The new sagittal height simulation software can accurately calculate the AC value of the orthokeratology lens suitable for the Chinese patients.