Fig. 2: Basic information and wearing conditions of ortho-k lens users.

The distribution, range and average of age (a), CVA (b), sleeping time on school days (c), and correction target (d) of ortho-k lens users. CVA corrected vision acuity, D dioptre. *The correction target of ortho-k lenses was defined as the sum of the spherical power plus half of the cylindrical power of the lens.