Axial length variation impacts on retinal vessel density and foveal avascular zone area measurement using optical coherence tomography angiography

2017 ◽  
Author(s):  
Danuta M. Sampson ◽  
Peijun Gong ◽  
Di An ◽  
Moreno Menghini ◽  
Alex Hansen ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Axial Length ◽  
Optical Coherence Tomography Angiography ◽  
Retinal Vessel ◽  
Area Measurement ◽  
Foveal Avascular Zone ◽  
Length Variation ◽  
Optical Coherence ◽  
Avascular Zone ◽  
Retinal Vessel Density

scholarly journals Evaluation of the Foveal Avascular Zone in Familial Exudative Vitreoretinopathy Using Optical Coherence Tomography Angiography

2020 ◽  
Author(s):  
Tetsuya Hasegawa ◽  
Misaki Hirato ◽  
Chieko Kobashi ◽  
Aya Yamaguchi ◽  
Rina Takagi ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Retinal Thickness ◽  
Deep Layer ◽  
Retinal Vessel ◽  
Foveal Avascular Zone ◽  
Control Group ◽  
Optical Coherence ◽  
Familial Exudative Vitreoretinopathy ◽  
Avascular Zone ◽  
Retinal Vessel Density

Abstract Background: To evaluate the foveal avascular zone (FAZ) and retinal structure in familial exudative vitreoretinopathy (FEVR).Methods: Twenty FEVR eyes with stage 1 or 2 disease and 20 control eyes were evaluated. The central retinal thickness (CRT), inner retinal thickness (IRT), surface retinal vessel density (SRVD), and deep retinal vessel density (DRVD) were measured using optical coherence tomography. The FAZ area was calculated using ImageJ software. The equivalent spherical value (SE) and axial length (AL) were measured. Results: The CRT (232±26.75 vs. 213.15 ± 16.138 μm; p=0.0003) and IRT (17.44±13.28 vs. 1.85 ± 5.696 μm; p=0.0005) were thicker in the FEVR group than in the control group. The surface FAZ area (0.26±0.1 vs. 0.33 ± 0.1 mm2; p=0.006) and the deep FAZ area (0.36±0.1 vs. 0.43 ± 0.1 mm2; p=0.037) were smaller in the FEVR group than in the control group. The SRVD values did not differ among the sectors, but the DRVD was higher in the FEVR group except for the inferior sector (superior, p=0.02; inferior, p=0.4; temporal, p=0.001; nasal, p=0.02). The SE and AL did not differ between the two groups. There was no correlation between the surface and deep layer FAZ area and age, CRT, SE, and AL. The surface, deep FAZ area, and IRT were correlated negatively (surface, r = −0.57, p=0.008; deep layer FAZ area, r = −0.5, p=0.02).Conclusion: Eyes with FEVR has a smaller FAZ because the inner retina with the vascular structure remained in the fovea.

scholarly journals Magnification Effect of Foveal Avascular Zone Measurement Using Optical Coherence Tomography Angiography

2020 ◽  
Vol 5 (2) ◽  
pp. 1-8
Author(s):  
Mika Suda ◽  
Yuji Yoshikawa ◽  
Gaku Terauchi ◽  
Soiti Matsumoto ◽  
Takuhei Shoji ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Axial Length ◽  
Optical Coherence Tomography Angiography ◽  
Foveal Avascular Zone ◽  
Optical Coherence ◽  
En Face ◽  
Avascular Zone ◽  
The Mean ◽  
The Relationship ◽  
Magnification Effect

Purpose: The aim of this study was to evaluate the foveal avascular zone (FAZ) of healthy subjects and examine the magnification effect. Methods: A total of 33 healthy volunteers were enrolled and all subjects were eligible for analysis. Optical coherence tomography angiography (OCTA) examination scanned 3 × 3 mm of the macular area. The FAZ area was measured on the superficial OCTA en face image with and without correction by axial length. The relationship between changes in the FAZ area after correction with the axial length was examined. Results: The mean age was 21.9 ± 0.6 years. The mean axial length was 24.87 ± 1.17 mm and mean spherical equivalent (SE) value was –3.64 ± 2.83 diopters (D). The FAZ area was 0.26 ± 0.10 mm2 before the axial length correction and 0.27 ± 0.10 mm2 after the correction. In the eyes that had an axial length longer than or equal to 26 mm or SE less than or equal to –6 D, the FAZ area after correction was significantly larger than that before correction (p < 0.01). The change of FAZ area after correction with axial length was significantly correlated with the axial length (R2 = 0.88, p < 0.01) or SE value (R2 = 0.55, p < 0.01). Conclusion: FAZ areas were comparable to previous reports. In high myopic cases, the magnification effect needs to be considered when evaluating the FAZ area.

scholarly journals Factors Affecting Repeatability of Assessment of the Retinal Microvasculature Using Optical Coherence Tomography Angiography in Healthy Subjects

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Taek Hoon Lee ◽  
Hyung Bin Lim ◽  
Ki Yup Nam ◽  
Kyeungmin Kim ◽  
Jung Yeul Kim
Keyword(s):  
Optical Coherence Tomography ◽  
Healthy Subjects ◽  
Optical Coherence Tomography Angiography ◽  
Signal Strength ◽  
Retinal Vessel ◽  
Foveal Avascular Zone ◽  
Optical Coherence ◽  
Factors Affecting ◽  
Retinal Microvasculature ◽  
Retinal Vessel Density

Abstract Various factors can affect repeatability of optical coherence tomography angiography (OCTA) measurements, and they have not been studied sufficiently. We aimed to investigate the factors associated with the repeatability of automated superficial retinal vessel density (VD) and foveal avascular zone (FAZ) metrics acquired from OCTA. A total of 141 normal eyes from 141 healthy subjects were included, and two consecutive macular 6 × 6-mm angiography scans were performed. VD, perfusion density (PD), and FAZ of the superficial capillary plexus were calculated automatically. Reproducibility was assessed based on intraclass correlations (ICCs) and coefficients of variation (CVs). VD (ICC: 0.824, CV: 3.898) and PD (ICC: 0.845, CV: 4.042) over the entire 6-mm scan area showed better repeatability than VD (ICC: 0.752, CV: 17.470) and PD (ICC: 0.752, CV: 18.552) in the 1-mm scan, and with respect to the obtained FAZ metrics (ICC < 0.75, CV > 10.0%). Regression analyses showed that two factors, signal strength (p = 0.004) and average VD over the total 6-mm scan area (p < 0.001), were significantly correlated with the CV of the VD. Signal strength was associated with the repeatability of OCTA measurements and should be considered in the analysis of retinal VD and FAZ.

scholarly journals Evaluation of the correlation between quantitative measurement of the foveal avascular zone and retinal vessel density and outer retinal disruptions in diabetic patients.

2019 ◽  
Author(s):  
NAGİHAN UĞURLU ◽  
AYŞE GÜZİN TAŞLIPINAR UZEL ◽  
AHMET ŞENGÜN ◽  
FATMA YÜLEK ◽  
DEMET ÖZDAŞ ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Retinal Vessel ◽  
Vessel Density ◽  
Foveal Avascular Zone ◽  
Diabetic Patients ◽  
Optical Coherence ◽  
Retinal Layers ◽  
Avascular Zone ◽  
Capillary Plexus ◽  
Retinal Vessel Density

Aim: The aim of the current study was to evaluate the correlation between the integrity of the outer retinal layers on optical coherence tomography (OCT) and objective parameters of retinal microvascular perfusion on optical coherence tomography angiography (OCTA). Method: 105 eyes of 54 diabetic patients were included in to the study. Integrity of the outer retinal layers including the external limiting membrane (ELM), ellipsoid zone (EZ), and interdigitation zone (IZ) were assessed by spectral-domain optical coherence tomography (SD-OCT). The foveal avascular zone (FAZ) area and vessel density (VD) measurements in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in all the Early Treatment Diabetic Retinopathy Study (ETDRS) sectors were evaluated by OCTA. Association between the quantitative measurement of the foveal avascular zone and retinal vessel density measurements and outer retinal disruptions were evaluated. Results: FAZ area was correlated with outer retinal layer disruption at both in the superficial plexus (r = 0.244, 0.228, 0.212, p = 0.013, 0.02, 0.031 for the ELM, EZ and IZ respectively) and deep capillary plexus (r = 0.298, 0.234, 0.197, p = 0.002, 0.019, 0.048 for the ELM, EZ and IZ respectively). A significant relationship was also found between the VD measurements in the SCP and DCP in ETDRS sectors and the outer retinal layers disruption. Conclusion: The result of the current study shows a significant relationship between the quantitative OCTA parameters and the integrity of the outer retinal layers and. This finding reveals a correlation between retinal capillary nonperfusion and outer retinal disruption in eyes with diabetic retinopathy. Key Words: Outer retinal disruption, external limiting membrane, ellipsoid zone, interdigitation zone, foveal avascular zone, superficial capillary plexus, deep capillary plexus, optical coherence tomography angiography

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