Posters

Comparison of keratometric values using Javal keratometer, Nidek automated kerato-refractometer and Orbscan II in patients with keratoconus and normal eyes

Poster Details

First Author: E.Seven TURKEY

Co Author(s):    M. Batur   F. Unal   T. Yasar              

Abstract Details

Purpose:

To assess the comparability of anterior corneal power values obtained from three different devices in patients with keratoconus and normal eyes.

Setting:

Yuzuncu Yil University, Faculty of Medicine, Department of Ophthalmology.

Methods:

Thiry-nine eyes were included in the study. Nineteen eyes of 39 eyes (group 1) was keratoconus and 20 of 39 eyes (group 2) was normal. Rabinowitz diagnostic criteria used for keratoconus diagnosis. Because of excessive high values could not measure by automated kerato-refractometer, so these eyes were not included in the study. Minimum (min-K) and maximum (max-K) keratometry readings and keratometric astigmatism with the latter two devices were compared with Javal. Student's t test was used for comparison average, standard deviation, minimum and maximum keratometric values of each groups.

Results:

Correlation coefficients for Javal and Orbscan II in measuring min-K and max-K were r=0.925 and r=0.785, respectively (p<0.01) in group 1, r=0.865 and r=0.927, respectively (p<0.01) in group 2. Correlation coefficients for Javal and Nidek automated kerato-refractometer in measuring min-K and max-K readings were very high r=0.921 and r=0.939, respectively (p<0.01) in group 1, r=0.955 and r=0.963, respectively (p<0.01) in group 2. The correlation between Nidek automated kerato-refractometer and Javal measurements of keratometric astigmatism was stronger than that for Orbscan II and Javal (r=0.705 and r=0.660) in group 1. The correlation between Orbscan II and Javal measurements of keratometric astigmatism was stronger than that for Nidek automated kerato-refractometer and Javal (r=0.608 and r=0.543) in group 2.

Conclusions:

Javal-type manual keratometers has been evaluated and approved in terms of its repeatability, and has been regarded as the gold standard in comparative studies. As shown in the results, Nidek-Javal correlations in measuring min-K and max-K were stronger than that between Orbscan II and Javal in group 1 and group 2. But, correlation in measurements min-K and max-K between Javal-Nidek and Javal-Orbscan were statistically significant (p<0.01) in group 1 and group 2. Based on these findings both Orbscan II and Nidek automated kerato-refractometer demonstrated strong correlations with Javal except some small differences.

Financial Disclosure:

NONE