Reliability Of Keratometry Measurements Obtained With Eye Surface Profilometry And Agreement Iol Master 500

To assess the repeatability of the keratometry parameters obtained with the Eye Surface Profiler (ESP) system and their agreement with the IOL Master 500 device.

Optometry Clinic of the University of Alicante, Spain. Department of Optics, Pharmacology and Anatomy, University of Alicante, Spain. 

Seventy-one eyes from 71 healthy participants were recruited. Three repeated measurements were performed with the ESP system. Simulated keratometry in the flat (SimKf) and steep (SimKs) meridians, astigmatism and axis were obtained. The same parameters were collected from the IOL Master 500 device. J0 and J45 vectors components of astigmatism were calculated. The intrasession repeatability was analyzed by using the within-subject standard deviation (Sw), and the intraclass correlation coefficient (ICC). The agreement was assessed using paired statistical tests and the Bland-Altman method.

The Sw was 0.07 mm, 0.04 mm, 0.51 D, 0.33 D and 0.22D, and the ICC was 0.96, 0.98, 0.74, 0.61 and 0.55 for SimKf, SimKs, astigmatism, J0 and J45, respectively. The mean difference and limits of agreement when comparing the ESP system with the IOL Master 500 device were 0.37 mm (0.08/0.66) for SimKf (p<0.001), 0.18 mm (0.00/0.35) for SimKs (p<0.001), -0.93 D (-2.42/0.56) for astigmatism (p<0.001), 0.51 D (-0.22/1.24) for J0 (p<0.001), and 0.06 D (-0.48/0.60) for J45 (p=0.09).

The ESP system provides consistent values for simulated keratometry, showing moderate consistency for astigmatism parameters. Contact lens practitioners should be aware that the ESP system and IOL Master 500 device provide different simulated keratometry from a clinically view-point.