Comparison of retinal nerve fiber layer thickness measurement bias and imprecision across three spectral-domain optical coherence tomography devices

• Published in: Investigative ophthalmology & visual science 2012-06, Vol.53 (7), p.3742-3747
• Main Authors: Buchser, Nancy M, Wollstein, Gadi, Ishikawa, Hiroshi, Bilonick, Richard A, Ling, Yun, Folio, Lindsey S, Kagemann, Larry, Noecker, Robert J, Albeiruti, Eiyass, Schuman, Joel S
• Format: Article
• Language: English
• Subjects: Aged; Female; Glaucoma - pathology; Humans; Imaging, Three-Dimensional; Male; Middle Aged; Nerve Fibers - pathology; Reproducibility of Results; Retina - pathology; Tomography, Optical Coherence - instrumentation
• ISSN: 1552-5783; 0146-0404; 1552-5783
• DOI: 10.1167/iovs.11-8432

We compared retinal nerve fiber layer (RNFL) bias and imprecision among three spectral-domain optical coherence tomographs (SD-OCT). A total of 152 eyes of 83 subjects (96 healthy and 56 glaucomatous eyes) underwent peripapillary RNFL imaging using at least 2 of the following 3 SD-OCT devices on the same day: Cirrus HD-OCT (optic nerve head [ONH]) cube 200 × 200 protocol), RTVue-100 (ONH protocol [12 radial lines and 13 concentric circles]), and 3D OCT-1000 (3D Scan 256 × 256 protocol). Calibration equations, bias and imprecision of RNFL measurements were calculated using structural equation models. The calibration equations for healthy and glaucoma RNFL thickness measurements among the 3 devices were: Cirrus = 2.136 + 0.831*RTVue; Cirrus = -15.521 + 1.056*3D OCT-1000; RTVue = -21.257 + 1.271*3D OCT-1000. Using Cirrus bias as an arbitrary reference, RTVue bias was 1.20 (95% CI 1.09-1.32, P < 0.05) times larger and 3D OCT-1000 was 0.95 (0.87-1.03, P > 0.05) times smaller. Relative to 3D OCT-1000, the RTVue bias was 1.27 (1.13-1.42, P < 0.05). RTVue imprecision (healthy eyes 7.83, 95% CI 6.43-9.58; glaucoma cases 5.71, 4.19-7.64) was statistically significantly higher than both Cirrus (healthy eyes 3.23, 2.11-4.31; glaucoma cases 3.53, 0.69-5.24) and 3D OCT-1000 (healthy eyes 4.07, 3.11-5.35; glaucoma cases 5.33, 3.77-7.67) in healthy eyes. The imprecision also was significantly higher for RTVue measurements in healthy compared to glaucomatous eyes. None of the other comparisons was statistically significant. RTVue-100 showed higher imprecision (or higher measurement variability) than Cirrus HD-OCT and 3D OCT-1000 RNFL measurements. Three-dimensional cube scanning with post-hoc data sampling may be a factor reducing imprecision.