Methods
MYOPIA
A total of 119 normal subjects with different myopia (not more than − 6D) were included. First, the resolution limit of discernible change in spherical power was derived based on the optical model. Then, the subjects were observed to see if they could perceive the changes in spherical power as per the resolution limit and compare the difference in the best-corrected visual acuity obtained with the resolution limit and interval of 0.25D.