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Automatic detection of modal spacing (Yellott's ring) in adaptive optics scanning light ophthalmoscope images
Purpose An impediment for the clinical utilisation of ophthalmic adaptive optics imaging systems is the automated assessment of photoreceptor mosaic integrity. Here we propose a fully automated algorithm for estimating photoreceptor density based on the radius of Yellott's ring. Methods The dis...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Wiley on behalf of American Geophysical Union
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3690144/ https://www.ncbi.nlm.nih.gov/pubmed/23668233 http://dx.doi.org/10.1111/opo.12070 |
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author | Cooper, Robert F Langlo, Christopher S Dubra, Alfredo Carroll, Joseph |
author_facet | Cooper, Robert F Langlo, Christopher S Dubra, Alfredo Carroll, Joseph |
author_sort | Cooper, Robert F |
collection | PubMed |
description | Purpose An impediment for the clinical utilisation of ophthalmic adaptive optics imaging systems is the automated assessment of photoreceptor mosaic integrity. Here we propose a fully automated algorithm for estimating photoreceptor density based on the radius of Yellott's ring. Methods The discrete Fourier transform (DFT) was used to obtain the power spectrum for a series of images of the human photoreceptor mosaic. Cell spacing is estimated by least-square fitting an annular pattern with a Gaussian cross section to the power spectrum; the radius of the resulting annulus provides an estimate of the modal spacing of the photoreceptors in the retinal image. The intrasession repeatability of the cone density estimates from the algorithm was evaluated, and the accuracy of the algorithm was validated against direct count estimates from a previous study. Accuracy in the presence of multiple cell types and disruptions in the mosaic was examined using images from four patients with retinal pathology and perifoveal images from two subjects with normal vision. Results Intrasession repeatability of the power spectrum method was comparable to a fully automated direct counting algorithm, but worse than that for the manually adjusted direct count values. In images of the normal parafoveal cone mosaic, we find good agreement between the power-spectrum derived density and that from the direct counting algorithm. In diseased eyes, the power spectrum method is insensitive to photoreceptor loss, with cone density estimates overestimating the density determined with direct counting. The automated power spectrum method also produced unreliable estimates of rod and cone density in perifoveal images of the photoreceptor mosaic, though manual correction of the initial algorithm output results in density estimates in better agreement with direct count values. Conclusions We developed and validated an automated algorithm based on the power spectrum for extracting estimates of cone spacing, from which estimates of density can be derived. This approach may be used to estimate cone density in images where not every single cone is visible, though caution is needed, as this robustness becomes a weakness when dealing with images from patients with some retinal diseases. This study represents an important first step in carefully assessing the relative utility of metrics for analysing the photoreceptor mosaic, and similar analyses of other metrics/algorithms are needed. |
format | Online Article Text |
id | pubmed-3690144 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Wiley on behalf of American Geophysical Union |
record_format | MEDLINE/PubMed |
spelling | pubmed-36901442014-01-29 Automatic detection of modal spacing (Yellott's ring) in adaptive optics scanning light ophthalmoscope images Cooper, Robert F Langlo, Christopher S Dubra, Alfredo Carroll, Joseph Ophthalmic Physiol Opt Original Articles Purpose An impediment for the clinical utilisation of ophthalmic adaptive optics imaging systems is the automated assessment of photoreceptor mosaic integrity. Here we propose a fully automated algorithm for estimating photoreceptor density based on the radius of Yellott's ring. Methods The discrete Fourier transform (DFT) was used to obtain the power spectrum for a series of images of the human photoreceptor mosaic. Cell spacing is estimated by least-square fitting an annular pattern with a Gaussian cross section to the power spectrum; the radius of the resulting annulus provides an estimate of the modal spacing of the photoreceptors in the retinal image. The intrasession repeatability of the cone density estimates from the algorithm was evaluated, and the accuracy of the algorithm was validated against direct count estimates from a previous study. Accuracy in the presence of multiple cell types and disruptions in the mosaic was examined using images from four patients with retinal pathology and perifoveal images from two subjects with normal vision. Results Intrasession repeatability of the power spectrum method was comparable to a fully automated direct counting algorithm, but worse than that for the manually adjusted direct count values. In images of the normal parafoveal cone mosaic, we find good agreement between the power-spectrum derived density and that from the direct counting algorithm. In diseased eyes, the power spectrum method is insensitive to photoreceptor loss, with cone density estimates overestimating the density determined with direct counting. The automated power spectrum method also produced unreliable estimates of rod and cone density in perifoveal images of the photoreceptor mosaic, though manual correction of the initial algorithm output results in density estimates in better agreement with direct count values. Conclusions We developed and validated an automated algorithm based on the power spectrum for extracting estimates of cone spacing, from which estimates of density can be derived. This approach may be used to estimate cone density in images where not every single cone is visible, though caution is needed, as this robustness becomes a weakness when dealing with images from patients with some retinal diseases. This study represents an important first step in carefully assessing the relative utility of metrics for analysing the photoreceptor mosaic, and similar analyses of other metrics/algorithms are needed. Wiley on behalf of American Geophysical Union 2013-07 2013-05-13 /pmc/articles/PMC3690144/ /pubmed/23668233 http://dx.doi.org/10.1111/opo.12070 Text en © 2013 The Authors Ophthalmic & Physiological Optics © 2013 The College of Optometrists Ophthalmic & Physiological Optics 33 (2013) 540–549 http://creativecommons.org/licenses/by/3.0/ This is an open access article under the terms of the Creative Commons Attribution Non–Commercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. |
spellingShingle | Original Articles Cooper, Robert F Langlo, Christopher S Dubra, Alfredo Carroll, Joseph Automatic detection of modal spacing (Yellott's ring) in adaptive optics scanning light ophthalmoscope images |
title | Automatic detection of modal spacing (Yellott's ring) in adaptive optics scanning light ophthalmoscope images |
title_full | Automatic detection of modal spacing (Yellott's ring) in adaptive optics scanning light ophthalmoscope images |
title_fullStr | Automatic detection of modal spacing (Yellott's ring) in adaptive optics scanning light ophthalmoscope images |
title_full_unstemmed | Automatic detection of modal spacing (Yellott's ring) in adaptive optics scanning light ophthalmoscope images |
title_short | Automatic detection of modal spacing (Yellott's ring) in adaptive optics scanning light ophthalmoscope images |
title_sort | automatic detection of modal spacing (yellott's ring) in adaptive optics scanning light ophthalmoscope images |
topic | Original Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3690144/ https://www.ncbi.nlm.nih.gov/pubmed/23668233 http://dx.doi.org/10.1111/opo.12070 |
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