Intraobserver and Interobserver Reliability and Reproducibility of Slit-Lamp-Adapted Optical Coherence Tomography (SL-OCT) for Evaluation of Anterior Chamber Depth and Central Corneal Thickness

Abstract

Purpose:: To evaluate the intra-observer and inter-observer reproducibility of anterior chamber depth (ACD) and central corneal thickness (CCT) measurements taken by SL-OCT, and to evaluate the concordance of CCT and ACD values obtained by SL-OCT with gold standard devices.

Methods:: Three images of each eye were taken by two different operators (operators 1 and 2) using SL-OCT. ACD and CCT values obtained by each operator were compared to one another and to ultrasonic pachymetry (CCT) and axial OCT biometry (ACD) values obtained by a third, masked operator (operator 3). Intra-operator and inter-operator reproducibility was assessed using Intraclass Correlation Coefficient (ICC). Repeated measures analysis of variance (ANOVA) was used to compare the measurements obtained from the three operators and Pearson Product Moment correlation was used to assess correlation between the measurements.

Results:: Forty-one eyes of healthy subjects were enrolled. Mean CCT was 0.556±0.020, 0.557±0.019, and 0.532±0.032 mm and mean ACD was 3.12±0.36, 3.13±0.38, and 3.50±0.44 mm for operators 1, 2, and 3, respectively. Overall differences between the means were significant (p<0.001, for both CCT and ACD). Intra-observer reproducibility for CCT (ICC of 0.948-0.995) and ACD (ICC of 0.972 -0.987) for all three operators was excellent. Inter-observer reproducibility between operators 1 and 2 for both CCT and ACD measurements were very good (r=0.845 and 0.951, respectively). Measured values for CCT were higher with SL-OCT as compared to ultrasonic pachymetry (p<0.001), whereas measured values for ACD were lower with SL-OCT as compared to axial OCT biometry (p<0.001).

Conclusions:: SL-OCT provides operator-independent, highly reproducible measures for both CCT and ACD. Further studies investigating the differences between SL-OCT, axial OCT biometry, and ultrasonic pachymetry will be needed before this data can be applied to clinical practice.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • anterior segment • anatomy