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Corneal thickness with CorVis ST and Pentacam in normal and keratoconic eyes

Session Details

Session Title: Imaging II

Session Date/Time: Monday 07/10/2013 | 16:30-18:00

Paper Time: 17:04

Venue: Main Lecture Hall (Ground Floor)

First Author: : J.Gonzalez-Meijome PORTUGAL

Co Author(s): :    D. Lopes-Ferreira   L. Rico-del-Viejo   J. Jorge   P. Neves   H. Ferreira   J.

Abstract Details

Purpose:

To evaluate the agreement between pachymetry data provided by a new instrument to measure intraocular pressure (IOP) and the biomechanical response of the cornea with the values provided by Pentacam at center (CCT) and at the thinnest point (MinCT).

Setting:

CEORLab - Center of Physics - University of Minho Hospital de S. Sebastićo - Sta. Maria da Feira - Portugal

Methods:

Fifty-four right eyes from healthy patients (32 females, 22 males) and 103 eyes from 60 keratoconus patients (23 females, 37 males) were included in the study. All patients were evaluated with Pentacam and Corvis ST (both from Oculus, Wetzlar, Germany) in random order in the same session. Pachymetry data provided by Corvis ST was compared with measurements of CCT and MinCT obtained with Pentacam for each population separately.

Results:

Average pachymetry provided by Corvis ST was 534±34 microns in the healthy population and 476±57 microns in the keratoconus population. Corvis ST underestimated pachymetry in the healthy corneas compared to CCT values provided by Pentacam (mean diff.=-4.3microns, 95% CI=-7.3 to -1.3microns; p=0.005), while comparison with Pentacam MinCT showed no differences (mean diff.=-1.3microns, 95% CI=-4.5 to 1.8microns). In the keratoconic population, differences between Corvis ST pachymetry and Pentacam were more significant (p>0.001). Corvis ST underestimates pachymetry when compared with CCT value provided by Pentacam (mean diff.=-11.1microns, 95% CI=-15.7 to -6.6microns), and overestimates pachymetry when compared with MinCT (mean diff.=+18.7microns, 95% CI=12.5 to 24.8microns). Considering the normal distribution of data, comparisons were performed using paired sample T-test.

Conclusions:

Corvis ST shows better agreement with MinCT than CCT values provided by Pentacam in normal corneas and the differences were quite below the clinically significant level. Converselly, in keratoconus patients, corneal pachymetry obtained from Corvis ST should not be considered interchangeable with values of CCT or MinCT obtained with Pentacam.

Financial Interest:

NONE