Comparison of corneal keratometric and equivalent total power measurements with a point-source color light-emitting diode-based topographer, a Scheimpflug imaging system, a laser interferometry and an image- guided system after refractive surgery

Session Details

Session Title: Investigations and Complications Management

Session Date/Time: Tuesday 13/09/2016 | 13:30-15:15

Paper Time: 13:36

Venue: Hall C3

First Author: : R.Ruiz-Mesa SPAIN

Co Author(s): :    A. Abengozar-Vela                    

Abstract Details

Purpose:

To compare corneal keratometric measurements and equivalent total power measurements using Cassini Total Corneal Astigmatism (i-Optics, The Hague, the Netherlands) with Pentacam (Optikgerate GmbH, Wetzlar, Germany), Verion Image Guided System (Alcon, Fort Worth, Texas) and Allegro BioGraph (Wavelight, Erlangen, Germany) in a group of post-refractive corneas.

Setting:

Oftalvist CIO Jerez, Jerez de la Frontera, Spain

Methods:

A prospective study was conducted in patients undergoing refractive surgery (LASIK, EBK and PRK). Three consecutive measurements were carried out randomly by Pentacam, Cassini, Biograph and Verion, and variables of anterior Sim-K and equivalent K-readings (EKR) were obtained. Correlation and repeatability were determined by the Spearman correlation coefficient and standard deviation. The difference between SimK and EKR were also compared.

Results:

A total of 25 post-refractive eyes from 13 patients have been enrolled. The mean Sim-K were 41.83 ± 2.72, 41.76 ± 2.57, 41.76 ± 2.84 and 42.20 ± 3.08 D with Cassini, Pentacam, Verion and Biograph, respectively. Mean EKR were 41.76 ± 2.79 and 41.30 ± 2.79 D for Cassini and Pentacam, respectively. The difference to Cassini EKR shows in average of 0.31, 0.20, 0.23, 0.17 with a maximum of 0.84, 0.66, 0.49, 0.41; to Pentacam EKR in average of 0.51, 0.51, 0.46, 0.54 and maximum of 1.43, 1.38, 1.42, 1.43D with SimK from Pentacam, Verion, Biograph and Cassini, respectively.

Conclusions:

The LED-based topographer Cassini showed similar repeatability and correlation in Sim-K values from Pentacam, Verion and Biograph after corneal refractive surgery. Both Cassini EKR and Pentacam EKR show unneglectable difference with SimK reveal unconventional anterior-posterior ratio for post-lasik corneas. Use SimK only in IOL calculation for post-refractive corneas may result refractive surprise. LED-based topographer Cassini is a reliable device for measuring refractive power in post-refractive corneas.

Financial Disclosure:

NONE