Selection of candidates to astigmatism correction combined with cataract intervention using two methods of corneal power measurement

Session Details

Session Title: Corneal Astigmatism Assessment. Surgery Equipment

Session Date/Time: Saturday 05/09/2015 | 11:00-13:00

Paper Time: 11:12

Venue: Main Auditorium

First Author: : U.de Sanctis ITALY

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

Abstract Details

Purpose:

To compare the impact of two methods of corneal power measurement on selection of candidates to astigmatism correction combined with cataract surgery.

Setting:

Department of Surgical Sciences, Ophthalmology Institute, University of Turin, Italy

Methods:

In one eye of 200 consecutive candidates to cataract surgery, the corneal astigmatism (CA) was measured using the simulated keratometry (CASimK) and total corneal power (CATCP) of Pentacam HR (Oculus, Wetzlar, Germany). Vector analysis was used to assess differences between methods in the estimate of CA. The X2 test was used to compare the proportion of eyes with CASimK and CATCP values above 1 diopter (D).

Results:

In the whole data-set, mean differences between CASimK and CATCP were -0.26 ± 0.26D x180°. In eyes with vertical, oblique and horizontal astigmatism, the mean difference was +0.24 ±0.26D x2°, -0.25 ±0.26D x176°, and -0.30 ± 0.26D x179° respectively. The proportion of eyes with CASimK and CATCP values above 1.00D was not statistically significant (p>0.05). In the whole dataset, it was 36.5% vs 38.5%. In eyes with vertical, oblique and horizontal astigmatism, it was 42.7% vs 32.6%, 11.4% vs 20.5% and 44.8% vs 58.2% respectively.

Conclusions:

With respect to CASimK, the CATCP underestimate the vertical astigmatism and overestimate the horizontal and oblique astigmatism. Using the CATCP values and the threshold of 1.00 D for the intervention, the proportion of candidates to the combined intervention of astigmatism and cataract would have been reduced by 10.1% in eyes with vertical astigmatism and increased by 13.4% in eyes with horizontal astigmatism.

Financial Interest:

NONE