Inter-Device Agreement of Keratometric and Astigmatic Measurements Between Manual and Modern Keratometers pre-FLACS
Kritika Chopra Kumar, Swati Tyagi* and Surbhi Aggarwal
ABSTRACT
Purpose: To compare the mean keratometry (K) readings and corneal astigmatism obtained from gold standard Manual keratometer with Automated keratometer, ORBSCAN II and IOLMaster 500 in patients undergoing Femto-second Laser Assisted Cataract Surgery (FLACS).
Methods: This prospective, non-randomized, comparative clinical study was done in 70 patients. A total of 120 eyes were included, each of which underwent keratometry with four different types of keratometers. Mean K values and corneal astigmatism were obtained from each machine and compared. Bland Altman plots were used to determine the 95% limits of agreement (LoA) between different devices.
Results: The Average K value from manual keratometer was 43.695±1.884(SD). Mean K from Auto-K was 43.686±1.917, ORBSCAN II was 43.748±1.865 and IOLMaster 500 was 43.685±1.875. Thus, keratometric values from all three newer devices correlated significantly (p ≤ 0.01) with the gold standard manual keratometer. In addition, the magnitude of corneal astigmatism measured by all three devices correlated significantly (p ≤ 0.01) with the gold standard manual keratometer.
Conclusion: The newer keratometers including Automated Keratometer, ORBSCAN II and IOLMaster 500 were found to be comparable to the gold standard Manual Keratometer. The keratometric readings and corneal astigmatism from each of the newer keratometers showed high degree of correlation with that of manual keratometer.
