Clinical comparison of automated and manual keratometry in pre-operative ocular biometry

Abstract

Corneal measurements, using the manual (Topcon OM-4) and automated (Canon RK-1) keratometers was performed on 104 eyes of 104 patients undergoing cataract and implant surgery to assess the role of automated keratometry in pre-operative ocular biometry. Four eyes of four patients were excluded from statistical analyses for various reasons. The time taken to perform automated keratometry was a mean of 61 (SD 21) seconds compared to 205 (SD 37) seconds for manual keratometry; the difference was statistically significant (p<0.001). In terms of the various keratometry values compared, mean K (corneal refractive power), flattest K, steepest K, astigmatism and the axis of astigmatism, 65% to 75% of the cases on automated keratometry were within 0.26 dioptres or 11° of manually determined values; the difference was statistically significant (p