Effect of the Eye Tracking System on the Reproducibility of Measurements Obtained With Spectral-domain Optical Coherence Tomography in Glaucoma.

Abstract

The purpose of this study was to evaluate whether the eye tracking system (ETS) improved the reproducibility of a single circle peripapillary retinal nerve fiber layer (RNFL) measurement acquired with spectral-domain optical coherence tomography (OCT). The sample comprised 205 individuals divided into 2 groups according to intraocular pressure and visual field outcomes. A total of 100 healthy individuals and 105 patients with open-angle glaucoma underwent imaging of the optic nerve head with OCT 3 times during the same session and 2 additional times in subsequent sessions (30 days apart). Intraclass correlation coefficient (ICC), coefficient of variation, and test-retest variability were calculated for the RNFL thickness acquired with and without the ETS enabled, and compared. The glaucoma group mainly comprised patients with moderate glaucoma (mean deviation of standard automated perimetry, -6.73±6.2 dB). The RNFL thicknesses did not differ between acquisitions with or without the ETS activated and disabled. All ICCs were >0.9 in the control and glaucoma groups with or without the ETS activated. The best parameter in the intersession analysis (with ETS activated) was global RNFL thickness (ICC, 0.95; coefficient of variation, 2.7%; and test-retest variability, 2.87 μm). The reproducibility and repeatability of RNFL measurements did not differ significantly between acquisitions with or without the ETS in either group. The reproducibility of peripapillary RNFL thicknesses acquired with OCT was excellent. The variability between OCT measurements did not decrease with the ETS activated.