Impact of Optical Coherence Tomography Scan Pattern and Chorio-Scleral Interface Delineation on Choroidal Vascularity Index Measurements

Kryshell Yu Qi Wong; Rachel Ka Man Chun; David Alonso-Caneiro; Yan Pui Chan; Andrew Kwok Cheung Lam

doi:10.1007/s44402-026-00159-4

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Impact of Optical Coherence Tomography Scan Pattern and Chorio-Scleral Interface Delineation on Choroidal Vascularity Index Measurements

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Impact of Optical Coherence Tomography Scan Pattern and Chorio-Scleral Interface Delineation on Choroidal Vascularity Index Measurements

Kryshell Yu Qi Wong, Rachel Ka Man Chun, David Alonso-Caneiro, Yan Pui Chan and Andrew Kwok Cheung Lam

Ophthalmic & Physiological Optics, Vol.Advanced access

15-Aug-2026

DOI: https://doi.org/10.1007/s44402-026-00159-4

PMID: 42603845

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Abstract

Chorio-scleral interface

Choroid

Choroidal thickness

Optical coherence tomography

Choroidal vascularity index

Scan pattern

Purpose To compare radial and horizontal raster acquisition patterns using spectral-domain optical coherence tomography (OCT) for assessing choroidal vascularity index (CVI) in healthy eyes and to evaluate how variability in chorio-scleral interface (CSI) delineation influences CVI measurements. Methods OCT images of 25 eyes from 25 healthy adults were acquired using 12-line radial and 31-line horizontal raster scans with enhanced depth imaging. CVI was measured manually using three different posterior boundaries—defined as the upper (vascular), middle (vascular–stromal) and lower (stromal) CSI boundaries. Agreement between CSI boundaries and scan patterns was assessed using Bland-Altman analysis. Topographical CVI variations across 6-mm Early Treatment of Diabetic Retinopathy Study (ETDRS) subfields, quadrants and rings were evaluated using two-way repeated-measures ANOVA. Results Participants were aged 21–31 years (72% female; mean spherical equivalent −2.97 ± 2.02 D). Mean CVI differences ranged from 1.43 to 2.38% between the upper and middle CSI boundaries and from 1.23 to 2.04% between the middle and lower CSI boundaries. Comparisons between the upper and lower CSI boundaries resulted in larger CVI differences, ranging from 2.90 to 4.42%. The coefficient of variation for CVI was low (<2%) between radial and raster scan patterns, and Bland-Altman analysis showed overall good agreement. The 31-line raster scan measured 0.51% higher CVI in the central foveal region, whereas the 12-line radial scan yielded 0.64–1.10% higher CVI in the perifoveal region. Significant mean differences were observed only in the outer temporal subfield (−1.10%, p = 0.005) and outer ring (−0.77%, p = 0.02). No significant scan-pattern effect was found, but CVI varied significantly across the ETDRS grid, with the lowest values in the outer nasal subfield, nasal quadrant and outer ring. Conclusions Radial scans provide CVI measurements comparable to raster scans, with faster acquisition, supporting practical use in children. Standardising CSI delineation is crucial for consistent CVI comparisons across studies.

Details

Title: Impact of Optical Coherence Tomography Scan Pattern and Chorio-Scleral Interface Delineation on Choroidal Vascularity Index Measurements
Authors: Kryshell Yu Qi Wong - Hong Kong Polytechnic University
Rachel Ka Man Chun - Hong Kong Polytechnic University
David Alonso-Caneiro - University of the Sunshine Coast
Yan Pui Chan - Hong Kong Science and Technology Parks Corporation
Andrew Kwok Cheung Lam (Corresponding Author) - Hong Kong Polytechnic University
Publication details: Ophthalmic & Physiological Optics, Vol.Advanced access
Publisher: Wiley-Blackwell Publishing Ltd.
DOI: 10.1007/s44402-026-00159-4
ISSN: 1475-1313
PMID: 42603845
Copyright note: This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Data Availability: The data that support the findings of this study are available from the corresponding author upon reasonable request.
Grant note: The authors gratefully acknowledge the funding support from the UGC Matching Grant Scheme (ZEZK).
Organisation Unit: School of Science, Technology and Engineering
Language: English
Record Identifier: 991254373602621
Output Type: Journal article

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