What should I bear in mind when I compare corneal power (K values) obtained with keratometers of different manufacturers?
Keratometers/ophthalmometers always measure the radius of the cornea. On one and the same eye (equal radius), different diopter values will be displayed due to the different eye models used by different manufacturers. (Refer to the table below for corneal refractive indices.) This may result in deviations of 0.5 to 0.8 D, which are to be attributed only to the eye model used, not to the actual measuring accuracy.
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