Título

CENTRAL CORNEAL THICKNESS MEASUREMENTS WITH SPECTRAL-DOMAIN AND SWEPT SOURCE ANTERIOR SEGMENT OPTICAL COHERENCE TOMOGRAPHY COMPARED WITH THE STANDARD ULTRASOUND PACHYMETRY

Objetivo

The aim of this study was to evaluate the agreement of the measurements of the central corneal thickness (CCT) using three different methods: anterior segment spectral-domain Optical Coherence tomography (AS SD-OCT), anterior segment swept-source optical coherence tomography (AS SS-OCT) and standard ultrasound pachymetry (US).

Método

Subjects with glaucoma presenting typical ONH findings, high intraocular pressure with or without visual field (VF) damage were included. Patients underwent AS SD-OCT (Spectralis, Heidelberg Engineering), AS SS-OCT (DRI-Triton, Topcon) and US. The US measurements were obtained by a trained examiner previously to the OCTs that were performed at the same day by a different trained examiner. For both the AS SD-OCT and AS SS-OCT, a 3mm horizontal single B-scan at the center of the cornea was performed. The measurements of the corneal thickness were performed by two blinded different trained examiners. Statistical analysis was performed using Interclass Correlation Coefficient (ICC) and Bland Altman analysis.

Resultado

26 eyes from 16 subjects were included. The mean (SD) age was 59.1 (±10.5) and 87% were females. The mean (SD) measurements were: AS SD-OCT: 548.04±33.11 µm; AS SS-OCT: 538.88±34.84 µm; US: 537.12±29.20 µm. The overall agreement was ICC=0.915, 95% CI [0.785-0.964]. The best agreement was between AS SS-OCT and US: ICC= 0.929, 95% CI [0.849-0.967]. The Bland Altman plots are depicted in figure 1. In the comparison between AS SS-OCT and US 53.8% eyes showed a difference less than 10 µm whereas the AS-SD OCT compared with US showed 50% of the eyes with a difference less than 10 µm.

Conclusão

Employing AS-OCT with two different iterations (SD-OCT and SS-OCT) to measure the CCT demonstrated comparable measurements to the standard US pachymetry. Both iterations of OCT provided a touchless and fast method which the examiner can define the exact place to scan the center of the cornea and obtain reliable measurements.