Caucasian infants are known to have a high incidence of astigmatism. The axis of greatest power is usually in the orientation orthogonal to the most common type found in Caucasian adults, with-the-rule astigmatism. We now find that Chinese infants also have a high incidence of astigmatism relative to adults, but its orientation is orthogonal to that of Caucasian infants. The source of this racial difference is not clear. It is unlikely to be due to the most obvious difference, the structure of the eyelids.
Adolescent Adult