Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

Danuta M Sampson, Peijun Gong, D. D. D. Miller, Moreno Menghini, Alex Hansen, David A Mackey, David D Sampson, Fred K. Chen

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Abstract

Purpose: To evaluate the impact of image magnification correction on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurements using optical coherence tomography angiography (OCTA).

Methods: Participants with healthy retinas were recruited for ocular biometry, refraction, and RTVue XR Avanti OCTA imaging with the 3 × 3-mm protocol. The foveal and parafoveal SRVD and FAZA were quantified with custom software before and after correction for magnification error using the Littman and the modified Bennett formulae. Relative changes between corrected and uncorrected SRVD and FAZA were calculated.

Results: Forty subjects were enrolled and the median (range) age of the participants was 30 (18-74) years. The mean (range) spherical equivalent refractive error was -1.65 (-8.00 to +4.88) diopters and mean (range) axial length was 24.42 mm (21.27-28.85). Images from 13 eyes were excluded due to poor image quality leaving 67 for analysis. Relative changes in foveal and parafoveal SRVD and FAZA after correction ranged from -20% to +10%, -3% to +2%, and -20% to +51%, respectively. Image size correction in measurements of foveal SRVD and FAZA was greater than 5% in 51% and 74% of eyes, respectively. In contrast, 100% of eyes had less than 5% correction in measurements of parafoveal SRVD.

Conclusions: Ocular biometry should be performed with OCTA to correct image magnification error induced by axial length variation. We advise caution when interpreting interocular and interindividual comparisons of SRVD and FAZA derived from OCTA without image size correction.

Original languageEnglish
Pages (from-to)3065-3072
Number of pages8
JournalInvestigative ophthalmology & visual science
Volume58
Issue number7
DOIs
Publication statusPublished - 1 Jun 2017

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Retinal Vessels
Optical Coherence Tomography
Angiography
Biometry
Ocular Refraction
Refractive Errors
Retina
Healthy Volunteers
Software

Cite this

@article{c39c8e951fea4882ab8b090e7a3f5bb8,
title = "Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography",
abstract = "Purpose: To evaluate the impact of image magnification correction on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurements using optical coherence tomography angiography (OCTA).Methods: Participants with healthy retinas were recruited for ocular biometry, refraction, and RTVue XR Avanti OCTA imaging with the 3 × 3-mm protocol. The foveal and parafoveal SRVD and FAZA were quantified with custom software before and after correction for magnification error using the Littman and the modified Bennett formulae. Relative changes between corrected and uncorrected SRVD and FAZA were calculated.Results: Forty subjects were enrolled and the median (range) age of the participants was 30 (18-74) years. The mean (range) spherical equivalent refractive error was -1.65 (-8.00 to +4.88) diopters and mean (range) axial length was 24.42 mm (21.27-28.85). Images from 13 eyes were excluded due to poor image quality leaving 67 for analysis. Relative changes in foveal and parafoveal SRVD and FAZA after correction ranged from -20{\%} to +10{\%}, -3{\%} to +2{\%}, and -20{\%} to +51{\%}, respectively. Image size correction in measurements of foveal SRVD and FAZA was greater than 5{\%} in 51{\%} and 74{\%} of eyes, respectively. In contrast, 100{\%} of eyes had less than 5{\%} correction in measurements of parafoveal SRVD.Conclusions: Ocular biometry should be performed with OCTA to correct image magnification error induced by axial length variation. We advise caution when interpreting interocular and interindividual comparisons of SRVD and FAZA derived from OCTA without image size correction.",
keywords = "Adolescent, Adult, Aged, Axial Length, Eye, Capillaries, Female, Fluorescein Angiography, Fovea Centralis, Fundus Oculi, Healthy Volunteers, Humans, Macula Lutea, Male, Middle Aged, Reproducibility of Results, Retinal Vessels, Tomography, Optical Coherence, Young Adult, Journal Article",
author = "Sampson, {Danuta M} and Peijun Gong and Miller, {D. D. D.} and Moreno Menghini and Alex Hansen and Mackey, {David A} and Sampson, {David D} and Chen, {Fred K.}",
year = "2017",
month = "6",
day = "1",
doi = "10.1167/iovs.17-21551",
language = "English",
volume = "58",
pages = "3065--3072",
journal = "Investigative Ophthalmology & Visual Science (IOVS)",
issn = "0146-0404",
publisher = "Association for Research in Vision and Ophthalmology (ARVO)",
number = "7",

}

TY - JOUR

T1 - Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

AU - Sampson, Danuta M

AU - Gong, Peijun

AU - Miller, D. D. D.

AU - Menghini, Moreno

AU - Hansen, Alex

AU - Mackey, David A

AU - Sampson, David D

AU - Chen, Fred K.

PY - 2017/6/1

Y1 - 2017/6/1

N2 - Purpose: To evaluate the impact of image magnification correction on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurements using optical coherence tomography angiography (OCTA).Methods: Participants with healthy retinas were recruited for ocular biometry, refraction, and RTVue XR Avanti OCTA imaging with the 3 × 3-mm protocol. The foveal and parafoveal SRVD and FAZA were quantified with custom software before and after correction for magnification error using the Littman and the modified Bennett formulae. Relative changes between corrected and uncorrected SRVD and FAZA were calculated.Results: Forty subjects were enrolled and the median (range) age of the participants was 30 (18-74) years. The mean (range) spherical equivalent refractive error was -1.65 (-8.00 to +4.88) diopters and mean (range) axial length was 24.42 mm (21.27-28.85). Images from 13 eyes were excluded due to poor image quality leaving 67 for analysis. Relative changes in foveal and parafoveal SRVD and FAZA after correction ranged from -20% to +10%, -3% to +2%, and -20% to +51%, respectively. Image size correction in measurements of foveal SRVD and FAZA was greater than 5% in 51% and 74% of eyes, respectively. In contrast, 100% of eyes had less than 5% correction in measurements of parafoveal SRVD.Conclusions: Ocular biometry should be performed with OCTA to correct image magnification error induced by axial length variation. We advise caution when interpreting interocular and interindividual comparisons of SRVD and FAZA derived from OCTA without image size correction.

AB - Purpose: To evaluate the impact of image magnification correction on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurements using optical coherence tomography angiography (OCTA).Methods: Participants with healthy retinas were recruited for ocular biometry, refraction, and RTVue XR Avanti OCTA imaging with the 3 × 3-mm protocol. The foveal and parafoveal SRVD and FAZA were quantified with custom software before and after correction for magnification error using the Littman and the modified Bennett formulae. Relative changes between corrected and uncorrected SRVD and FAZA were calculated.Results: Forty subjects were enrolled and the median (range) age of the participants was 30 (18-74) years. The mean (range) spherical equivalent refractive error was -1.65 (-8.00 to +4.88) diopters and mean (range) axial length was 24.42 mm (21.27-28.85). Images from 13 eyes were excluded due to poor image quality leaving 67 for analysis. Relative changes in foveal and parafoveal SRVD and FAZA after correction ranged from -20% to +10%, -3% to +2%, and -20% to +51%, respectively. Image size correction in measurements of foveal SRVD and FAZA was greater than 5% in 51% and 74% of eyes, respectively. In contrast, 100% of eyes had less than 5% correction in measurements of parafoveal SRVD.Conclusions: Ocular biometry should be performed with OCTA to correct image magnification error induced by axial length variation. We advise caution when interpreting interocular and interindividual comparisons of SRVD and FAZA derived from OCTA without image size correction.

KW - Adolescent

KW - Adult

KW - Aged

KW - Axial Length, Eye

KW - Capillaries

KW - Female

KW - Fluorescein Angiography

KW - Fovea Centralis

KW - Fundus Oculi

KW - Healthy Volunteers

KW - Humans

KW - Macula Lutea

KW - Male

KW - Middle Aged

KW - Reproducibility of Results

KW - Retinal Vessels

KW - Tomography, Optical Coherence

KW - Young Adult

KW - Journal Article

U2 - 10.1167/iovs.17-21551

DO - 10.1167/iovs.17-21551

M3 - Article

VL - 58

SP - 3065

EP - 3072

JO - Investigative Ophthalmology & Visual Science (IOVS)

JF - Investigative Ophthalmology & Visual Science (IOVS)

SN - 0146-0404

IS - 7

ER -