Posters

Repeatability and comparison of astigmatism measurements by Pentacam corneal ray tracing and IOLMaster automated keratometry in patients with cataract

Poster Details

First Author: U. de Sanctis ITALY

Co Author(s):    C. Casale   R. Penna   P. Donna   F. Grignolo           

Abstract Details

Purpose:

To assess the repeatability of corneal astigmatism measurements by a ray-tracing (total corneal refractive power; CATCRP) and by an anterior surface-based method (CAIOL Master) and to compare the methods in patients with cataract.

Setting:

Eye Clinic, University of Turin, Italy.

Methods:

In one eye of 107 cataract surgery candidates, CATCRP was measured twice using a Pentacam HR (Oculus, Wetzlar, Germany) and CAIOL Master using an IOL Master 500 (Carl Zeiss Meditec, Jena, Germany). Method repeatability was assessed by calculating vector differences between first and second measurements. Vector differences between first measurements were calculated to compare CATCRP and CAIOL Master in the whole dataset and in eyes stratified by CATCRP steep meridian alignment.

Results:

Unlike CATCRP, the vector difference between repeated measurements was statistically significant for CAIOL Master (mean difference: 0.01D x23° versus 0.08D x47°; p=0.79 versus p=0.02, respectively). Overall, the aggregate value of CATCRP was higher (p<0.001) than that of CAIOL Master (0.32D X 5° versus 0.20D X 25°) and vector differences between methods were >0.50D in 59.8% of cases. As compared with CAIOL Master, the aggregate value of CATCRP was lower (0.71Dx88° versus 0.91Dx86°; p=0.01) in eyes with vertical alignment and higher (1.05Dx1° versus 0.79Dx6°; p<0.001) in eyes with horizontal astigmatism.

Conclusions:

CATCRP was more repeatable than CA IOL Master in patients with cataract. As compared with CAIOL Master, CATCRP underestimated vertical and overestimated horizontal astigmatism. Vector differences between methods were >0.50D in over half of cases.

Financial Disclosure:

NONE