scholarly journals Personalized analysis of foveal avascular zone with optical coherence tomography angiography

2017 ◽  
Vol 10 (4) ◽  
pp. 32-40
Author(s):  
Maria A Burnasheva ◽  
Alexey N Kulikov ◽  
Dmitrii S Maltsev
Keyword(s):  
Optical Coherence Tomography ◽  
Healthy Subjects ◽  
Optical Coherence Tomography Angiography ◽  
Foveal Avascular Zone ◽  
Optical Coherence ◽  
Free Zone ◽  
Avascular Zone ◽  
The Mean ◽  
The Relationship ◽  
Free Area

Aim. To investigate the relationship between the foveal avascular zone (FAZ) and inner nuclear layer (INL) - free zone in order to provide a personalized approach for evaluation of the FAZ area with optical coherence tomography-angiography (OCTA). Material and methods. Thirty-six healthy individuals (36 eyes) and 9 patients (12 eyes) with nonproliferative diabetic retinopathy (nPDR) were included in this study. The FAZ area as well as INL-free zone were measured in superficial capillary plexus on OCTA images. The FAZ area, INL-free area, and the ratio of the INL-free area to the FAZ area were compared between healthy subjects and nPDR patients. Results. The mean FAZ area in healthy subjects and nPDR patients was 0.33 ± 0.1 and 0.56 ± 0.28 mm2 (p < 0.05), respectively. The mean INL-free zone in healthy subjects and nPDR patients was 0.33 ± 0.07 and 0.28 ± 0.1 mm2 (p > 0.05), respectively. The ratio of the INL-free area to the FAZ area in healthy subjects and nPDR patients was 1.08 ± 0.25 and 0.57 ± 0.2 (p < 0.001), respectively. Receiver operating characteristic analysis showed that the ratio of the INL-free area to the FAZ area had the higher area under curve (0.98; 91.7% sensitivity and 97.2% specificity) compared to the FAZ area (0.8; 66.7% sensitivity and 87.1% specificity) for differentiating nPDR from healthy eyes. Conclusion. This study showed that personalized analysis of the FAZ area based on the relationship between the actual FAZ and INL-free zone has better diagnostic accuracy compared to the conventional FAZ area measurement on OCTA images. (For citation: Burnasheva MA, Kulikov AN, Maltsev DS. Personalized analysis of foveal avascular zone with optical coherence tomography angiography. ­Ophthalmology Journal. 2017;10(4):32-40. doi: 10.17816/OV10432-40).

scholarly journals Comparison of Superficial and Deep Foveal Avascular Zone Area in Healthy Subjects Using Two Spectral Domain Optical Coherence Tomography Angiography Devices

2020 ◽  
Author(s):  
Pasha Anvari ◽  
Amin Najafi ◽  
Reza Mirshahi ◽  
Mahsa Sardarinia ◽  
Maryam Ashrafkhorasani ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Healthy Subjects ◽  
Optical Coherence Tomography Angiography ◽  
Spectral Domain ◽  
Foveal Avascular Zone ◽  
Retinal Layer ◽  
Optical Coherence ◽  
Retinal Layers ◽  
Avascular Zone ◽  
The Mean

Purpose: To compare the area of the foveal avascular zone (FAZ) in the superficial and deep retinal layers using two different spectral-domain optical coherence tomography angiography (OCTA) devices. Methods: A cross-sectional comparative study was conducted to obtain macular OCTA images from healthy subjects using Optovue RTVue XR Avanti (Optovue, Inc, Fremont, CA) and Spectralis HRA+OCTA (Heidelberg Engineering, Heidelberg, Germany). Two independent trained graders measured the FAZ area using automated slab segmentation. The FAZ area in the superficial and deep retinal layers were compared. Results: Twenty-three eyes of 23 subjects were included. The graders agreement was excellent (>0.86) for all measurements. The mean FAZ area was significantly larger at the superficial retinal layer as compared to the deep retinal layer on both devices (0.31 ± 0.08 mm2 vs 0.26 ± 0.08 mm2 in Optovue and 0.55 ± 0.16 mm2 vs 0.36 ± 0.13 mm2 in Spectralis, both P < 0.001). The mean FAZ area was significantly greater in the superficial and deep retinal layers using Spectralis as compared to Optovue measurements (P < 0.001 for both comparisons). Conclusion: In contrast to previous reports, the FAZ area was larger in the superficial retina as compared to deep retinal layers using updated software versions. Measurements from different devices cannot be used interchangeably.

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.

Quantitative assessment of the effect of fasting on macular microcirculation: an optical coherence tomography angiography study

2019 ◽  
Vol 104 (8) ◽  
pp. 1098-1102
Author(s):  
Yalçın Karaküçük ◽  
Abdullah Beyoglu ◽  
Ayşegül Çömez
Keyword(s):  
Optical Coherence Tomography ◽  
Healthy Subjects ◽  
Optical Coherence Tomography Angiography ◽  
Foveal Avascular Zone ◽  
Ophthalmological Examination ◽  
Optical Coherence ◽  
Flow Area ◽  
Fasting Period ◽  
Avascular Zone ◽  
The Mean

AimTo analyse the effect of fasting on the retinal vascular plexus and choriocapillaris structures in healthy subjects via Optical Coherence Tomography Angiography (OCTA).MethodsIn this prospective study, OCTA scans of 98 eyes in 49 healthy subjects were compared in fasting and non-fasting period. All cases had a full ophthalmological examination, with OCTA parameters measured, including superficial flow area (SCP) (mm2), deep flow area (DCP) (mm2), choriocapillaris flow area (CC) (mm2), superficial and deep vascular density (SVD and DVD, respectively) (%), superficial foveal avascular zone area (FAZs) (mm2), deep foveal avascular zone area (FAZd) (mm2), subfoveal choroidal thickness (SFCT) (µm) and central macular thickness (CMT) (µm).ResultsThe mean SCP, DCP and CC flow area values were induced to be significantly lower in a fasting than a non-fasting period (p<0.001, p<0.001, p=0.049, respectively). The mean VD in a fasting period was statistically significantly lower than in a non-fasting period at the SCP level (p=0.009). No statistically significant difference was found between the two periods in respect to DVD, FAZd and CMT (p=0.068, p=0.653 and p=0.531, respectively); however, FAZs were significantly lower in a non-fasting than fasting period (p=0.038). The SFCT was determined to be statistically significant and thicker during a fasting period (p<0.001).ConclusionThe current study documented several physiological changes in a fasting period, such as changes in SCP, DCP, CC flow, SVD and DVD, via OCTA.

scholarly journals Automatic segmentation of foveal avascular zone based on adaptive watershed algorithm in retinal optical coherence tomography angiography images

2021 ◽  
Author(s):  
Jian Liu ◽  
Shixin Yan ◽  
Nan Lu ◽  
Dongni Yang ◽  
Chunhui Fan ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Healthy Subjects ◽  
Optical Coherence Tomography Angiography ◽  
Automatic Segmentation ◽  
Qualitative Evaluation ◽  
Foveal Avascular Zone ◽  
Watershed Algorithm ◽  
Strong Positive Correlation ◽  
Optical Coherence ◽  
Avascular Zone

The size and shape of the foveal avascular zone (FAZ) have a strong positive correlation with several vision-threatening retinovascular diseases. The identification, segmentation and analysis of FAZ are of great significance to clinical diagnosis and treatment. We presented an adaptive watershed algorithm to automatically extract FAZ from retinal optical coherence tomography angiography (OCTA) images. For the traditional watershed algorithm, “over-segmentation” is the most common problem. FAZ is often incorrectly divided into multiple regions by redundant “dams”. This paper analyzed the relationship between the “dams” length and the maximum inscribed circle radius of FAZ, and proposed an adaptive watershed algorithm to solve the problem of “over-segmentation”. Here, 132 healthy retinal images and 50 diabetic retinopathy (DR) images were used to verify the accuracy and stability of the algorithm. Three ophthalmologists were invited to make quantitative and qualitative evaluations on the segmentation results of this algorithm. The quantitative evaluation results show that the correlation coefficients between the automatic and manual segmentation results are 0.945 (in healthy subjects) and 0.927 (in DR patients), respectively. For qualitative evaluation, the percentages of “perfect segmentation” (score of 3) and “good segmentation” (score of 2) are 99.4% (in healthy subjects) and 98.7% (in DR patients), respectively. This work promotes the application of watershed algorithm in FAZ segmentation, making it a useful tool for analyzing and diagnosing eye diseases.

Optical coherence tomography angiography findings in young β-thalassemia patients

2020 ◽  
Vol 30 (3) ◽  
pp. 600-607
Author(s):  
Elif Güler Kazancı ◽  
Muhammet Furkan Korkmaz ◽  
Mehmet Erol Can
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Foveal Avascular Zone ◽  
Control Group ◽  
Study Group ◽  
Optical Coherence ◽  
Avascular Zone ◽  
Capillary Plexus ◽  
The Mean ◽  
Superficial Capillary Plexus

Purpose: The purpose was to evaluate retinal vascular parameters by optical coherence tomography angiography in β-thalassemia major patients. Methods: Thirty-three patients with β-thalassemia major (study group) and 29 healthy children (control group) were enrolled in the study. All subjects underwent a complete ocular examination. The mean foveal avascular zone, non-flow area, foveal avascular zone perimeter, acircularity index of foveal avascular zone, foveal density, the superficial capillary plexus, and deep capillary plexus were scanned using 6 × 6 mm optical coherence tomography angiography scans centered on the macula. Superficial capillary plexus and deep capillary plexus were also scanned centered on the optic disk. We collected data on histories of patients, and hemoglobin and ferritin were also studied from both groups. Results: The mean age was 13.85 ± 4.69 years (range: 4–21 years) in β-thalassemia major group and 12.59 ± 3.66 years (range: 6–18 years) in the control group. The mean foveal avascular zone value was 0.265 ± 0.11 mm2 in the study group and 0.296 ± 0.12 mm2 in the control group. The mean non-flow area value was 0.468 ± 0.12 mm2 in the study group and 0.479 ± 0.14 mm2 in the control group ( p > 0.05). Differences in the mean values for foveal density and acircularity index were statistically significant between the study group and control group ( p < 0.05, p = 0.026, and p = 0.026, respectively). Superficial capillary plexus and deep capillary plexus were not a significant difference between the study and control groups in 6 × 6 mm scans on macula and 4.5 × 4.5 mm scans on optic disk area ( p > 0.05). Acircularity index was negatively correlated ( r = −0.292, p = 0.026), and foveal density was positively correlated with hemoglobin ( r = 0.292, p = 0.026). Conclusion: By using optical coherence tomography angiography, we detected foveal microvascular changes in young β-thalassemia patients before significant ocular anomalies development.

Reproducibility and Repeatability of Foveal Avascular Zone Area Measurements Using Swept-Source Optical Coherence Tomography Angiography in Healthy Subjects

2016 ◽  
Vol 27 (3) ◽  
pp. 336-341 ◽  
Author(s):  
Rodolfo Mastropasqua ◽  
Lisa Toto ◽  
Peter A. Mattei ◽  
Marta Di Nicola ◽  
Isaia A.L. Zecca ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Healthy Subjects ◽  
Optical Coherence Tomography Angiography ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Foveal Avascular Zone ◽  
Optical Coherence ◽  
Swept Source ◽  
Avascular Zone ◽  
Within Subjects

Purpose To assess the reproducibility and repeatability of foveal avascular zone (FAZ) area measurements using swept-source optical coherence tomography angiography (SS-OCTA) in healthy subjects. Methods Sixty-four eyes of 64 healthy volunteers were randomly subjected to FAZ area measurements using SS-OCTA by 2 examiners in 2 different sessions. Results The FAZ areas measured by the first and second observer were 0.269 ± 0.092 mm2 and 0.270 ± 0.090 mm2, respectively. Within subjects, the coefficients of variations were 2.44% (95% confidence interval [CI] 1.95% to 2.93%) and 2.66% (95% CI 2.00% to 3.31%) for the first and second observers, respectively. The coefficient of repeatability average measurements of FAZ area were 0.021 mm2 and 0.024 mm2. The intraclass correlation coefficient values were 0.993 (95% CI 0.989 to 0.996) and 0.991 (95% CI 0.986 to 0.995). Interobserver and intraobserver concordance correlation coefficients ranged from 0.998 (95% CI 0.997 to 0.999) to 0.999 (95% CI 0.998 to 0.999) and from 0.989 (95% CI 0.982 to 0.993) to 0.987 (95% CI 0.979 to 0.992), respectively. Conclusions The FAZ area measurements by means of SS-OCTA showed high reproducibility and repeatability in healthy eyes.

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