Ball-bearing keratometry.
We obtained steel test balls for keratometer calibration at nominal cost by using a selected set of steel ball bearings, readily available for nonoptical purposes. The set of keratometer tests balls each have an accuracy of greater than one part in 1,000.
D003315:Cornea / Q000033:anatomy & histology*; D006801:Humans; D008722:Methods; D012029:Refraction, Ocular / Q000295:instrumentation