Rates of childhood myopia progression as a function of type of astigmatism

This study examines the relation of rate of childhood myopia progression to the type of astigmatism exhibited. Longitudinal records of myopia progression were collected from five optometry practices in the USA. Patients were classified as having with-the-rule (WTR) astigmatism, zero astigmatism or against-the-rule (ATR) astigmatism. Rates of myopia progression for both principal meridians in the right eye were calculated by linear regression. Rates of myopia progression were not significantly different in the three astigmatism groups. Rates of astigmatism change were much less in magnitude than rates of myopia progression, but were significantly different in the three astigmatism groups. WTR astigmats are likely to change in the WTR direction, while ATR astigmats are likely to change in the ATR direction.