Posters

Comparison of keratometry measurements obtained by 3 different devices and a standard manual keratometer

Poster Details

First Author: S.Aslan Bayhan TURKEY

Co Author(s):    H. Bayhan   E. Muhafiz   I. Can              

Abstract Details

Purpose:

To compare the corneal curvature measurements of Lenstar LS 900 optical low coherence reflectometry (OLCR), Sirius Scheimpflug-Placido topographer, Reichert auto-kerato-refractometer (AKR) and Javal manual keratometer (MK).

Setting:

Bozok University Faculty of Medicine Ophthalmology Department, Yozgat ,Turkey.

Methods:

In this prospective study 48 eyes of 48 patients were included. After detailed ophthalmologic examination three repeated measurements of keratometry were obtained using all devices. The average of the consecutive measurements for each device was used to compare the keratometry values between devices. Bland-Altman plots were used to assess agreement among the instruments, and 95% limits of agreement (LoA) for each comparison were calculated.

Results:

The mean keratometry measurements by OLCR, Scheimpflug-Placido topographer, AKR, and MK were 44.20±1.36 D, 44.14±1.38 D, 44.30±1.39, and 44.42±1.34 D, respectively. The mean differences (and upper/lower LoA) for keratometry measurements were 0.04 D (0.53/-0.44) between OLCR and Scheimpflug-Placido topographer, -0.03 (0.76/-0.82) between OLCR and AKR, -0.24 (0.24/-0.71) between OLCR and MK, -0.28 (0.28/-0.84) between Scheimpflug-Placido topographer -MK, -0.08 (0.85/-1.01) between Scheimpflug-Placido topographer-AKR, and -0.22 (0.63/-1.07) between AKR- MK. All 4 modalities of keratometry measurements correlated closely with each other, with Pearson correlation coefficients ranging from 0.941 to 0.984.

Conclusions:

These keratometers can differ considerably for some clinical applications in measuring corneal curvature. Because the postoperative visual outcome with toric intraocular lens implantation may be optimised by correct analysis of biometry data, special attention to any difference in corneal astigmatism caused by different instruments should be noted.

Financial Disclosure:

NONE