Accuracy of computer-assisted vertical cup-to-disk ratio grading for glaucoma screening

Blake M. Snyder; Sang Min Nam; Preeyanuch Khunsongkiet; Sakarin Ausayakhun; Thidarat Leeungurasatien; Maxwell R. Leiter; Artem Sevastopolsky; Ashlin S. Joye; Elyse J. Berlinberg; Yingna Liu; David A. Ramirez; Caitlin A. Moe; Somsanguan Ausayakhun; Robert L. Stamper; Jeremy D. Keenan

doi:10.1371/journal.pone.0220362

Accuracy of computer-assisted vertical cup-to-disk ratio grading for glaucoma screening

Blake M. Snyder, Sang Min Nam, Preeyanuch Khunsongkiet, Sakarin Ausayakhun, Thidarat Leeungurasatien, Maxwell R. Leiter, Artem Sevastopolsky, Ashlin S. Joye, Elyse J. Berlinberg, Yingna Liu, David A. Ramirez, Caitlin A. Moe, Somsanguan Ausayakhun, Robert L. Stamper, Jeremy D. Keenan^*

^*Corresponding author for this work

Ophthalmology

Research output: Contribution to journal › Article › peer-review

5 Scopus citations

Abstract

Purpose Glaucoma screening can be performed by assessing the vertical-cup-to-disk ratio (VCDR) of the optic nerve head from fundus photography, but VCDR grading is inherently subjective. This study investigated whether computer software could improve the accuracy and repeatability of VCDR assessment. Methods In this cross-sectional diagnostic accuracy study, 5 ophthalmologists independently assessed the VCDR from a set of 200 optic disk images, with the median grade used as the reference standard for subsequent analyses. Eight non-ophthalmologists graded each image by two different methods: by visual inspection and with assistance from a custom-made publicly available software program. Agreement with the reference standard grade was assessed for each method by calculating the intraclass correlation coefficient (ICC), and the sensitivity and specificity determined relative to a median ophthalmologist grade of 0.7. Results VCDR grades ranged from 0.1 to 0.9 for visual assessment and from 0.1 to 1.0 for software-assisted grading, with a median grade of 0.4 for each. Agreement between each of the 8 graders and the reference standard was higher for visual inspection (median ICC 0.65, interquartile range 0.57 to 0.82) than for software-assisted grading (median ICC 0.59, IQR 0.44 to 0.71); P = 0.02, Wilcoxon signed-rank test). Visual inspection and software assistance had similar sensitivity and specificity for detecting glaucomatous cupping. Conclusion The computer software used in this study did not improve the reproducibility or validity of VCDR grading from fundus photographs compared with simple visual inspection. More clinical experience was correlated with higher agreement with the ophthalmologist VCDR reference standard.

Original language	English (US)
Article number	e0220362
Journal	PloS one
Volume	14
Issue number	8
DOIs	https://doi.org/10.1371/journal.pone.0220362
State	Published - Aug 1 2019

Funding

This work was supported in part by the Doris Duke Charitable Foundation through a grant supporting the Doris Duke International Clinical Research Fellows Program at the University of California San Francisco School of Medicine. Blake M. Snyder is a Doris Duke International Clinical Research Fellow. Additional support came from the Fortisure Foundation, the JaMel and Tom Perkins Family Foundation, That Man May See, and Research to Prevent Blindness. The funders provided support in the form of salaries for authors [AS], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.

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Snyder, B. M., Nam, S. M., Khunsongkiet, P., Ausayakhun, S., Leeungurasatien, T., Leiter, M. R., Sevastopolsky, A., Joye, A. S., Berlinberg, E. J., Liu, Y., Ramirez, D. A., Moe, C. A., Ausayakhun, S., Stamper, R. L., & Keenan, J. D. (2019). Accuracy of computer-assisted vertical cup-to-disk ratio grading for glaucoma screening. PloS one, 14(8), Article e0220362. https://doi.org/10.1371/journal.pone.0220362

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title = "Accuracy of computer-assisted vertical cup-to-disk ratio grading for glaucoma screening",

abstract = "Purpose Glaucoma screening can be performed by assessing the vertical-cup-to-disk ratio (VCDR) of the optic nerve head from fundus photography, but VCDR grading is inherently subjective. This study investigated whether computer software could improve the accuracy and repeatability of VCDR assessment. Methods In this cross-sectional diagnostic accuracy study, 5 ophthalmologists independently assessed the VCDR from a set of 200 optic disk images, with the median grade used as the reference standard for subsequent analyses. Eight non-ophthalmologists graded each image by two different methods: by visual inspection and with assistance from a custom-made publicly available software program. Agreement with the reference standard grade was assessed for each method by calculating the intraclass correlation coefficient (ICC), and the sensitivity and specificity determined relative to a median ophthalmologist grade of 0.7. Results VCDR grades ranged from 0.1 to 0.9 for visual assessment and from 0.1 to 1.0 for software-assisted grading, with a median grade of 0.4 for each. Agreement between each of the 8 graders and the reference standard was higher for visual inspection (median ICC 0.65, interquartile range 0.57 to 0.82) than for software-assisted grading (median ICC 0.59, IQR 0.44 to 0.71); P = 0.02, Wilcoxon signed-rank test). Visual inspection and software assistance had similar sensitivity and specificity for detecting glaucomatous cupping. Conclusion The computer software used in this study did not improve the reproducibility or validity of VCDR grading from fundus photographs compared with simple visual inspection. More clinical experience was correlated with higher agreement with the ophthalmologist VCDR reference standard.",

author = "Snyder, {Blake M.} and Nam, {Sang Min} and Preeyanuch Khunsongkiet and Sakarin Ausayakhun and Thidarat Leeungurasatien and Leiter, {Maxwell R.} and Artem Sevastopolsky and Joye, {Ashlin S.} and Berlinberg, {Elyse J.} and Yingna Liu and Ramirez, {David A.} and Moe, {Caitlin A.} and Somsanguan Ausayakhun and Stamper, {Robert L.} and Keenan, {Jeremy D.}",

note = "Publisher Copyright: {\textcopyright} 2019 Snyder et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.",

year = "2019",

month = aug,

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Snyder, BM, Nam, SM, Khunsongkiet, P, Ausayakhun, S, Leeungurasatien, T, Leiter, MR, Sevastopolsky, A, Joye, AS, Berlinberg, EJ, Liu, Y, Ramirez, DA, Moe, CA, Ausayakhun, S, Stamper, RL & Keenan, JD 2019, 'Accuracy of computer-assisted vertical cup-to-disk ratio grading for glaucoma screening', PloS one, vol. 14, no. 8, e0220362. https://doi.org/10.1371/journal.pone.0220362

TY - JOUR

T1 - Accuracy of computer-assisted vertical cup-to-disk ratio grading for glaucoma screening

AU - Snyder, Blake M.

AU - Nam, Sang Min

AU - Khunsongkiet, Preeyanuch

AU - Ausayakhun, Sakarin

AU - Leeungurasatien, Thidarat

AU - Leiter, Maxwell R.

AU - Sevastopolsky, Artem

AU - Joye, Ashlin S.

AU - Berlinberg, Elyse J.

AU - Liu, Yingna

AU - Ramirez, David A.

AU - Moe, Caitlin A.

AU - Ausayakhun, Somsanguan

AU - Stamper, Robert L.

AU - Keenan, Jeremy D.

N1 - Publisher Copyright: © 2019 Snyder et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

PY - 2019/8/1

Y1 - 2019/8/1

N2 - Purpose Glaucoma screening can be performed by assessing the vertical-cup-to-disk ratio (VCDR) of the optic nerve head from fundus photography, but VCDR grading is inherently subjective. This study investigated whether computer software could improve the accuracy and repeatability of VCDR assessment. Methods In this cross-sectional diagnostic accuracy study, 5 ophthalmologists independently assessed the VCDR from a set of 200 optic disk images, with the median grade used as the reference standard for subsequent analyses. Eight non-ophthalmologists graded each image by two different methods: by visual inspection and with assistance from a custom-made publicly available software program. Agreement with the reference standard grade was assessed for each method by calculating the intraclass correlation coefficient (ICC), and the sensitivity and specificity determined relative to a median ophthalmologist grade of 0.7. Results VCDR grades ranged from 0.1 to 0.9 for visual assessment and from 0.1 to 1.0 for software-assisted grading, with a median grade of 0.4 for each. Agreement between each of the 8 graders and the reference standard was higher for visual inspection (median ICC 0.65, interquartile range 0.57 to 0.82) than for software-assisted grading (median ICC 0.59, IQR 0.44 to 0.71); P = 0.02, Wilcoxon signed-rank test). Visual inspection and software assistance had similar sensitivity and specificity for detecting glaucomatous cupping. Conclusion The computer software used in this study did not improve the reproducibility or validity of VCDR grading from fundus photographs compared with simple visual inspection. More clinical experience was correlated with higher agreement with the ophthalmologist VCDR reference standard.

AB - Purpose Glaucoma screening can be performed by assessing the vertical-cup-to-disk ratio (VCDR) of the optic nerve head from fundus photography, but VCDR grading is inherently subjective. This study investigated whether computer software could improve the accuracy and repeatability of VCDR assessment. Methods In this cross-sectional diagnostic accuracy study, 5 ophthalmologists independently assessed the VCDR from a set of 200 optic disk images, with the median grade used as the reference standard for subsequent analyses. Eight non-ophthalmologists graded each image by two different methods: by visual inspection and with assistance from a custom-made publicly available software program. Agreement with the reference standard grade was assessed for each method by calculating the intraclass correlation coefficient (ICC), and the sensitivity and specificity determined relative to a median ophthalmologist grade of 0.7. Results VCDR grades ranged from 0.1 to 0.9 for visual assessment and from 0.1 to 1.0 for software-assisted grading, with a median grade of 0.4 for each. Agreement between each of the 8 graders and the reference standard was higher for visual inspection (median ICC 0.65, interquartile range 0.57 to 0.82) than for software-assisted grading (median ICC 0.59, IQR 0.44 to 0.71); P = 0.02, Wilcoxon signed-rank test). Visual inspection and software assistance had similar sensitivity and specificity for detecting glaucomatous cupping. Conclusion The computer software used in this study did not improve the reproducibility or validity of VCDR grading from fundus photographs compared with simple visual inspection. More clinical experience was correlated with higher agreement with the ophthalmologist VCDR reference standard.

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Accuracy of computer-assisted vertical cup-to-disk ratio grading for glaucoma screening

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