Posters

Corneal morphological characterization for detection of keratoconus: isolated Scheimpflug camera system vs combined Scheimpflug-placido disc topography

Poster Details

First Author: N. Moura-Coelho PORTUGAL

Co Author(s): J. Paulo Cunha   A. Luisa Basilio   C. Pereira Bruxelas   M. Dutra Medeiros   P. Candelaria        

Abstract Details

Purpose:

To evaluate the agreement between anterior segment parameters (ASP) as measured by isolated Scheimpflug camera topography versus combined Scheimpflug-Placido disc topography in eyes with keratoconus (KC) and KC suspects.

Setting:

Centro Hospitalar Lisbon Central (CHLC, EPE)

Methods:

Cross-sectional study of eyes with KC or KC suspects who underwent Sirius Scheimpflug Analyzer® and Pentacam HR® evaluation. The following ASP were measured and compared: anterior chamber depth (ACD, mm); corneal volume (CV, mm3); pachymetry at apex (AT, μm) and at thinnest point (TP, μm); keratometry (mean front K, mean back K, maximum front K, D); high-order aberrations (RMS-HOA, μm); coma (RMS-Coma, μm); spherical aberrations (RMS-SA, μm); astigmatism (RMS-Astigm, μm). Statistical analysis was performed using the IBM SPSS Statistics 19® tool.

Results:

36 eyes were studied and divided into 2 groups according to Sirius® normative database: KC suspects (G1=19 eyes) and KC (G2=17 eyes). 5 eyes of the G1 group were classified as “possible KC” by the Pentacam® system. In G1, measurements showed agreement for ACD, AT, mean front K and RMS-Coma; in G2, ACD, AT, TP, RMS-Coma and RMS-Astigm measurements showed agreement as well. The remaining ASP measured showed statistically significant differences or proportionality bias between the 2 topographers.

Conclusions:

Combined Scheimpflug-Placido topographers may allow more precise topometric, topographic and wavefront analysis compared to Pentacam®, and may detect more cases of suspect corneas or sublinical KC. However, some of the ASP measurements didn’t show agreement and should thus not be used interchangeably.

Financial Disclosure:

None