Variation in the inter-day corneal thickness measurements performed with Corvis ST vs Pentacam in healthy corneas: a comparative study

Session Details

Session Title: Corneal Biomechanics

Session Date/Time: Sunday 15/09/2019 | 16:30-18:00

Paper Time: 16:42

Venue: Free Paper Forum: Podium 4

First Author: : S.Rodrigo Rey SPAIN

Co Author(s): :    R. Cañones-Zafra   M. García-González   P. Drake   I. Rodriguez   G. Bolivar-de Miguel   M. Teus              

Abstract Details

Purpose:

To assess the precision of central corneal thickness (CCT) inter-day measurements obtained by a Scheimpflug technology (Corvis ST, Oculus) and to compare the measured values with those obtained by the high resolution rotating Scheimpflug camera (Pentacam, Oculus) and ultrasound contact pachymetry (USP).

Setting:

Department of Ophthalmology of Príncipe de Asturias University Hospital, Alcalá de Henares, Madrid, Spain.

Methods:

CCT was measured in sixty eyes of 30 healthy subjects at different central corneal locations with the Pentacam system (thinnest-CT, apical-CT and central pupil-CT). Two consecutive valid scans were recorded at each shot. Measurements were repeated at the same hour in three different days. Afterwards, six consecutive measurements were obtained with USP. Finally, two examinations separated a minimum of 30 minutes were made with the Corvis ST at each day. The within-subject standard deviation (Sw) and coefficient of variation (CoV) were calculated to compare the repeatability between the different pachymetry devices.

Results:

Mean CCT value obtained with Corvis was 513.48±42.10μm. Mean CCT values obtained with Pentacam were 541,29±36.14μm for central cornea spots, 537,70±36.58μm, 543,93±35.69μm, 542,25±35.90μm for thinnest-CT, apical-CT and central pupil-CT respectively. Mean USP-CCT was531,57±39.74μm. Good reproducibility was found for the three devices, with a CoV of 2.57% for Corvis, 1.10% for Pentacam central points(1.02%, 0.95% and 0.96% to thinnest-CT, apical-CT and central pupil-CT respectively), and a CoV of 2.54% for USP-measurements. Statistically significant differences were found in repeatability between Pentacam and Corvis data and between Pentacam and USP(p<0.05).

Conclusions:

In the assessment of healthy corneas CCT, the Corvis system seems to achieve a good repeatability in measuring inter-day corneal thickness, however Pentacam obtained a higher level of repeatability and a higher precision than those achieved by Corvis ST and USP. Thus, in healthy corneas, Pentacam would be a more reliable method than the other pachymetry devices evaluated assessing CCT.

Financial Disclosure:

None