Agreement of optical coherence tomography thickness measurements between Heidelberg Eye Explorer and ImageJ software

Abstract

Objective: To investigate the agreement and correlation of manual central foveal thickness (CFT) measurements using the Heidelberg Eye Explorer and ImageJ software.

Methods: Optical coherence tomography (OCT) images were identified. CFT was measured using the Heidelberg Eye Explorer caliper tool. Two independent graders measured the CFT of the same images using ImageJ software. A Pearson correlation coefficient, intraclass correlation coefficient, Bland-Altman plots, and coefficient of repeatability were used to assess the agreement and correlation between the Heidelberg Eye Explorer and ImageJ measurements.

Results: One-hundred and twenty-two OCT images from 91 patients were analyzed. Mean CFT as measured using the Heidelberg caliper tool was 264.8 ± 113 µm. Using ImageJ software, graders 1 and 2 obtained mean CFT values of 267 ± 114.3 µm and 270 ± 114.8 µm, respectively. Pearson correlation revealed a strong correlation between the Heidelberg and Image J measurements (r = 0.999, p < 0.0001). Bland-Altman plots noted a less than 4 µm mean difference between Heidelberg and ImageJ CFT values (2.67 ± 3.46 and 3.72 ± 2.78 µm for graders 1 and 2, respectively).

Conclusion: There was strong agreement between the Heidelberg Eye Explorer and ImageJ software for manual CFT measurements. ImageJ may be a reliable tool for thickness measurements when proprietary OCT software is unavailable.