MEASUREMENT OF CORNEAL ASTIGMATISM

Cornea is the most important optical surface in the eye dioptric syste m. Three kinds of methods in measuring corneal astigmatism were used. Three hundred and sixty eyes suffered ametropia were selected on a ran dom basis. Computer-assisted corneal topographic system was compared w ith keratometer and cycloplegic,retinoscopy in measuring corneal curva ture. There was no statistical difference in axes of astigmatism among the three groups. It is thought that Delta K-sim could show the corne al regular astigmatism. As for diopters of astitigmatism, no differenc e was found between the groups of corneal topography and keratometer, but there was a significant difference between the group of cycloplegi c retinoscopy and the other two groups. It was demonstrated that kerat ometer could function similarly as the corneal topography. However, it measured only four points from a small region of the cornea and was l imited in measuring slight changes in corneal curvature. Some discussi on was also made about the graphic patterns and Delta K-sim in corneal topography.