Analysis of refractive status of Hong Kong Chinese infants.

Recently developed methods of quantifying changing dioptric power are applied to the refractive status of Hong Kong Chinese infants from about 10 to about 40 weeks of age. The analysis confirms that hyperopia decreases during the period and that with-the-rule astigmatism predominates. Change, however, is not constant over the period. The rate of decrease of hyperopia slows down and the refractive status becomes more spherical. The mean refractive status is calculated at 10, 20, 30 and 40 weeks. The spread of refractive status is represented by variance-covariance matrices calculated for each group and 95% confidence ellipsoids on the mean are constructed. The variance-covariance exhibits little change over the period. The right and left eyes show similar behaviour.