Partial Coherence Laser Interferometry versus Autokeratometry in Measuring Corneal Curvature in a Malay Population

Abstract

Abstract: : Purpose:Few studies have evaluated the accuracy of corneal curvature measurements by the IOL master. The purpose of this prospective study was to compare measurement of corneal curvature between the autokeratometer and the IOL Master in a group of randomly selected Malays between the ages of 40–79 years. Methods: 83 subjects (n=83, mean age=56.8, male:female=28:55) were included in this comparative study. The corneal curvature of the right eye were measured by automated keratometer (Canon RK 5 Auto Ref–Keratometer, Canon Inc Ltd., Japan), followed by IOL Master (Carl Zeiss, Germany). Two readings (one each at the horizontal and vertical meridians) were taken with the autokeratometer, while six readings (three each at the horizontal and vertical meridians) were taken with the IOL Master. The mean of the readings obtained through the two methods are obtained. Results: Measurements taken with the autokeratometer were generally higher than those taken with the IOL Master ( mean ± SD of the difference between autokeratometer and IOL Master readings being 0.048 ± 0.044 mm). The corneal curvature measurements performed by both the autokeratometer and IOL Master were highly correlated (Pearson’s correlation coefficient 0.985). A Bland–Altman plot showed that the 95% limits of agreement between the two methods lay between 0.135 and –0.039 mm. Conclusions:High correlation in keratometry readings between the autokeratometer and IOL Master and the autokeratometer suggests that both instruments may be used interchangeably. In performing biometry prior to cataract surgery. the IOL Master may be used to measure both the axial length and corneal curvature, obviating the need to use 2 separate instruments.

Keywords: anterior segment • clinical (human) or epidemiologic studies: systems/equipment/techniques