Corneal changes in schoolchildren.

Videokeratography (TMS-1) data from the right eyes of 788 children between the ages of 6 and 14 years, examined in 1994 as part of the Orinda Longitudinal Study of Myopia, were analyzed using the Fast Fourier Transform (FFT) to quantify corneal power, toricity, and toricity axis. Cross-sectional analysis showed no statistically significant age trend for these parameters. Conversely, longitudinal analysis of data for 387 of these children, first measured in 1991, showed a statistically significant decrease in corneal power. Corneal toricity did not change significantly over this 3-year period, although there was a minute but statistically significant clockwise axis shift. From this we conclude that in the elementary and junior high school years-during which period axial length is known to increase-corneal flattening continues, but corneal toricity is stable.