COMPARISON OF KERATOMETRIC READINGS AS OBTAINED BY THE JAVAL OPHTHALMOMETER, HELMHOLTZ KERATOMETER AND EYE SYS CORNEAL ANALYSIS SYSTEM

Astigmatism and corneal power were established by a triple procedure i n a study at 100 eyes at 50 young subjects using the Helmholtz keratom eter, Javal ophthalmometer and Eye Sys corneal analysis system. Mean k eratometric astigmatism was significantly different between the three instruments. The average central corneal power was significantly diffe rent, giving slightly lower values with the Eye Sys system than with t he Helmholtz keratometer. In the low astigmatisms, there was no differ ence by using the Helmholtz and Javal instruments, but the difference was significant between Helmholtz and Eye Sys, and highly significant between the Javal and video keratoscope. Medium and high corneal astig matisms did not show significant differences with any of the three ins truments. When compared with the video keratoscope, Helmholtz and Java l instruments gave astigmatism values by excess or defect respectively . In low astigmatism, there was no difference between Helmholtz and Ja val ophthalmometers, although a difference was apparent between them a nd the Eye Sys system. In the light of these differences, an optimum p ractical procedure of examination can be established to evaluate corne al parameters.