Cross-Device Field-of-View Scale Differences in Clinical OCT Angiography: Phantom Calibration and Large-Scale Clinical Validation
- 1University of Washington
Abstract
PurposeDevice-specific field-of-view (FOV) may affect quantitative optical coherence tomography angiography (OCTA) metrics. This study quantifies inter-device FOV scale differences across four commonly used clinical OCTA devices.
MethodsFour devices were evaluated under a nominal 6x6 mm (or 20{degrees}x20{degrees}) scanning protocol: Zeiss Cirrus, Heidelberg Spectralis, Topcon Triton, and Topcon Maestro2. Device-specific spatial scale was assessed by (1) phantom calibration using a model eye with a 1x1 mm checkerboard, computing scale factors relative to Zeiss Cirrus; and (2) in vivo validation, registering same-eye, same-visit retinal images from the three devices to those of Zeiss Cirrus and extracting scale factors from the transformation matrices. Correlation between DICOM-implied FOV and spherical equivalent (SE) was assessed, where DICOM-implied FOV equals pixel-spacing x image-dimension.
ResultsPhantom measurements showed that Spectralis, Triton, and Maestro2 each captured a systematically smaller FOV than Cirrus, with geometric mean scale factors of 0.933, 0.954, and 0.967. The same pattern was observed across 801 eyes from 556 participants, giving geometric mean scale factors of 0.939, 0.943, and 0.960, agreeing with phantom estimates within 1.2%. DICOM-implied FOV was fixed at 6.000x6.000 mm for three devices but varied from 5.212x5.209 to 6.743x6.739 mm for Spectralis, correlating with SE ({rho} = -0.635, P < 0.001).
ConclusionSystematic FOV discrepancies exist across clinical OCTA devices despite nominally identical protocols, and DICOM pixel-spacing should be interpreted with caution as a spatial measure.
Translational RelevanceThe reported device-specific scale factors could serve as magnification corrections for quantitative OCTA metrics, addressing the systematic spatial inter-device discrepancies.
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BibTeX
@misc{zhang2026crossdevice,
title = {{Cross-Device Field-of-View Scale Differences in Clinical OCT Angiography: Phantom Calibration and Large-Scale Clinical Validation}},
author = {Y. Zhang and Z. Gong and V.-H. Le and B. S. Kumar and Y. Shi and S. Wang and Y. Jiang and C. Duong and S. Henry and C. Yun and Y. Wu and A. Lee and C. Lee and R. Wang},
howpublished = {medRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.04.26361850},
url = {https://www.medrxiv.org/content/10.64898/2026.09.04.26361850v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Cross-Device Field-of-View Scale Differences in Clinical OCT Angiography: Phantom Calibration and Large-Scale Clinical Validation
AU - Y. Zhang
AU - Z. Gong
AU - V.-H. Le
AU - B. S. Kumar
AU - Y. Shi
AU - S. Wang
AU - Y. Jiang
AU - C. Duong
AU - S. Henry
AU - C. Yun
AU - Y. Wu
AU - A. Lee
AU - C. Lee
AU - R. Wang
PY - 2026
DA - 2026/09/04
PB - medRxiv
DO - 10.64898/2026.09.04.26361850
UR - https://www.medrxiv.org/content/10.64898/2026.09.04.26361850v1
AB - PurposeDevice-specific field-of-view (FOV) may affect quantitative optical coherence tomography angiography (OCTA) metrics. This study quantifies inter-device FOV scale differences across four commonly used clinical OCTA devices. MethodsFour devices were evaluated under a nominal 6x6 mm (or 20{degrees}x20{degrees}) scanning protocol: Zeiss Cirrus, Heidelberg Spectralis, Topcon Triton, and Topcon Maestro2. Device-specific spatial scale was assessed by (1) phantom calibration using a model eye with a 1x1 mm checkerboard, computing scale factors relative to Zeiss Cirrus; and (2) in vivo validation, registering same-eye, same-visit retinal images from the three devices to those of Zeiss Cirrus and extracting scale factors from the transformation matrices. Correlation between DICOM-implied FOV and spherical equivalent (SE) was assessed, where DICOM-implied FOV equals pixel-spacing x image-dimension. ResultsPhantom measurements showed that Spectralis, Triton, and Maestro2 each captured a systematically smaller FOV than Cirrus, with geometric mean scale factors of 0.933, 0.954, and 0.967. The same pattern was observed across 801 eyes from 556 participants, giving geometric mean scale factors of 0.939, 0.943, and 0.960, agreeing with phantom estimates within 1.2%. DICOM-implied FOV was fixed at 6.000x6.000 mm for three devices but varied from 5.212x5.209 to 6.743x6.739 mm for Spectralis, correlating with SE ({rho} = -0.635, P < 0.001). ConclusionSystematic FOV discrepancies exist across clinical OCTA devices despite nominally identical protocols, and DICOM pixel-spacing should be interpreted with caution as a spatial measure. Translational RelevanceThe reported device-specific scale factors could serve as magnification corrections for quantitative OCTA metrics, addressing the systematic spatial inter-device discrepancies.
ER -