Astigmatism in children: changes in axis and amount from birth to six years.

Noncycloplegic refractions of 1,000 children aged 0-6 years revealed a high incidence of astigmatism, especially in the first 2 years of life. Before age 41/2 years, most of the astigmatism was against-the-rule and after that age most was with-the-rule. Of 19 children who did not show astigmatism in the first year, only one acquired it by 4 years. Of 29 children who had large amounts of astigmatism in the first year, all showed elimination or a large reduction in the amount of the cylindrical error by 4 years. These results are relevant to the etiology of astigmatism.