Corneal refraction and topography in school myopia.

Changes in corneal refraction and topography among 145 myopic children were monitored over a three-year period as part of a clinical trial of myopia treatment. The spherical equivalent of the right eye increased from -1.46 D to -3.13 D. Refractive astigmatism increased from 0.28 D to 0.46. Corneal astigmatism, horizontal and vertical corneal curvatures, as well as shape factors, did not change significantly. The mean deviation of the corneal apex from the visual axis increased from 0.48 mm to 0.67 mm. Girls showed steeper corneal curvatures than boys. For both sexes the vertical corneal curvatures were steeper, and shape factors were smaller than those along the horizontal plane. Axial elongation of the eye was the primary explanation for myopic progression.