Correcting magnification error in foveal avascular zone area measurements of optical coherence tomography angiography images with estimated axial length
Abstract Background To generate and validate a method to estimate axial length estimated (ALest) from spherical equivalent (SE) and corneal curvature [keratometry (K)], and to determine if this ALest can replace actual axial length (ALact) for correcting transverse magnification error in optical coh...
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| Format: | Article |
| Language: | English |
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BMC
2022-08-01
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| Series: | Eye and Vision |
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| Online Access: | https://doi.org/10.1186/s40662-022-00299-x |
| _version_ | 1798038064430317568 |
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| author | Deepaysh D. C. S. Dutt Seyhan Yazar Jason Charng David A. Mackey Fred K. Chen Danuta M. Sampson |
| author_facet | Deepaysh D. C. S. Dutt Seyhan Yazar Jason Charng David A. Mackey Fred K. Chen Danuta M. Sampson |
| author_sort | Deepaysh D. C. S. Dutt |
| collection | DOAJ |
| description | Abstract Background To generate and validate a method to estimate axial length estimated (ALest) from spherical equivalent (SE) and corneal curvature [keratometry (K)], and to determine if this ALest can replace actual axial length (ALact) for correcting transverse magnification error in optical coherence tomography angiography (OCTA) images using the Littmann-Bennett formula. Methods Data from 1301 participants of the Raine Study Gen2-20 year follow-up were divided into two datasets to generate (n = 650) and validate (n = 651) a relationship between AL, SE, and K. The developed formula was then applied to a separate dataset of 46 participants with AL, SE, and K measurements and OCTA images to estimate and compare the performance of ALest against ALact in correcting transverse magnification error in OCTA images when measuring the foveal avascular zone area (FAZA). Results The formula for ALest yielded the equation: ALest = 2.102K − 0.4125SE + 7.268, R2 = 0.794. There was good agreement between ALest and ALact for both study cohorts. The mean difference [standard deviation (SD)] between FAZA corrected with ALest and ALact was 0.002 (0.015) mm2 with the 95% limits of agreement (LoA) of − 0.027 to 0.031 mm2. In comparison, mean difference (SD) between FAZA uncorrected and corrected with ALact was − 0.005 (0.030) mm2, with 95% LoA of − 0.064 to 0.054 mm2. Conclusions ALact is more accurate than ALest and hence should be used preferentially in magnification error correction in the clinical setting. FAZA corrected with ALest is comparable to FAZA corrected with ALact, while FAZA measurements using images corrected with ALest have a greater accuracy than measurements on uncorrected images. Hence, in the absence of ALact, clinicians should use ALest to correct for magnification error as this provides for more accurate measurements of fundus parameters than uncorrected images. |
| first_indexed | 2024-04-11T21:36:11Z |
| format | Article |
| id | doaj.art-c93fe973c05e48b9b03e1401b0ff88ff |
| institution | Directory Open Access Journal |
| issn | 2326-0254 |
| language | English |
| last_indexed | 2024-04-11T21:36:11Z |
| publishDate | 2022-08-01 |
| publisher | BMC |
| record_format | Article |
| series | Eye and Vision |
| spelling | doaj.art-c93fe973c05e48b9b03e1401b0ff88ff2022-12-22T04:01:46ZengBMCEye and Vision2326-02542022-08-019111010.1186/s40662-022-00299-xCorrecting magnification error in foveal avascular zone area measurements of optical coherence tomography angiography images with estimated axial lengthDeepaysh D. C. S. Dutt0Seyhan Yazar1Jason Charng2David A. Mackey3Fred K. Chen4Danuta M. Sampson5Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western AustraliaCentre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western AustraliaCentre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western AustraliaCentre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western AustraliaCentre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western AustraliaCentre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western AustraliaAbstract Background To generate and validate a method to estimate axial length estimated (ALest) from spherical equivalent (SE) and corneal curvature [keratometry (K)], and to determine if this ALest can replace actual axial length (ALact) for correcting transverse magnification error in optical coherence tomography angiography (OCTA) images using the Littmann-Bennett formula. Methods Data from 1301 participants of the Raine Study Gen2-20 year follow-up were divided into two datasets to generate (n = 650) and validate (n = 651) a relationship between AL, SE, and K. The developed formula was then applied to a separate dataset of 46 participants with AL, SE, and K measurements and OCTA images to estimate and compare the performance of ALest against ALact in correcting transverse magnification error in OCTA images when measuring the foveal avascular zone area (FAZA). Results The formula for ALest yielded the equation: ALest = 2.102K − 0.4125SE + 7.268, R2 = 0.794. There was good agreement between ALest and ALact for both study cohorts. The mean difference [standard deviation (SD)] between FAZA corrected with ALest and ALact was 0.002 (0.015) mm2 with the 95% limits of agreement (LoA) of − 0.027 to 0.031 mm2. In comparison, mean difference (SD) between FAZA uncorrected and corrected with ALact was − 0.005 (0.030) mm2, with 95% LoA of − 0.064 to 0.054 mm2. Conclusions ALact is more accurate than ALest and hence should be used preferentially in magnification error correction in the clinical setting. FAZA corrected with ALest is comparable to FAZA corrected with ALact, while FAZA measurements using images corrected with ALest have a greater accuracy than measurements on uncorrected images. Hence, in the absence of ALact, clinicians should use ALest to correct for magnification error as this provides for more accurate measurements of fundus parameters than uncorrected images.https://doi.org/10.1186/s40662-022-00299-xOCTAKeratometrySpherical equivalentAxial lengthLittmann-Bennett formula |
| spellingShingle | Deepaysh D. C. S. Dutt Seyhan Yazar Jason Charng David A. Mackey Fred K. Chen Danuta M. Sampson Correcting magnification error in foveal avascular zone area measurements of optical coherence tomography angiography images with estimated axial length Eye and Vision OCTA Keratometry Spherical equivalent Axial length Littmann-Bennett formula |
| title | Correcting magnification error in foveal avascular zone area measurements of optical coherence tomography angiography images with estimated axial length |
| title_full | Correcting magnification error in foveal avascular zone area measurements of optical coherence tomography angiography images with estimated axial length |
| title_fullStr | Correcting magnification error in foveal avascular zone area measurements of optical coherence tomography angiography images with estimated axial length |
| title_full_unstemmed | Correcting magnification error in foveal avascular zone area measurements of optical coherence tomography angiography images with estimated axial length |
| title_short | Correcting magnification error in foveal avascular zone area measurements of optical coherence tomography angiography images with estimated axial length |
| title_sort | correcting magnification error in foveal avascular zone area measurements of optical coherence tomography angiography images with estimated axial length |
| topic | OCTA Keratometry Spherical equivalent Axial length Littmann-Bennett formula |
| url | https://doi.org/10.1186/s40662-022-00299-x |
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