scholarly journals Morphological Characteristics of Normal Foveal Avascular Zone by Optical Coherence Tomography Angiography

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Zeiad Eldaly ◽  
Wael Soliman ◽  
Mohamed Sharaf ◽  
Ali Natag Reyad
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Morphological Characteristics ◽  
Qualitative Assessment ◽  
Foveal Avascular Zone ◽  
Optical Coherence ◽  
Vertical Diameter ◽  
Quantitative Measurements ◽  
Horizontal Diameter ◽  
Avascular Zone

Purpose. To provide quantitative measurements for the foveal avascular zone (FAZ) and to describe its morphological characteristics by optical coherence tomography angiography (OCT-A). Design. Cross-sectional observational case series. Methods. Healthy volunteers were recruited and evaluated using Triton-DRI SS-OCT Angiography. A 4.5 × 4.5 mm square was evaluated by OCT-A center around the fovea. Superficial and deep capillary plexus were identified, and different quantitative measurements were conducted along with categorization of the FAZ pattern. Results. Eighty-two eyes (41 volunteers) were evaluated. Mean age was 30.59 ± 7.6 years (23–42 years). Mean subcentral retinal thickness was 200.1 ± 5.66 um (192–210 um). The number of terminal vessels was variable (range, 8–11). Mean maximum terminal vessel-to-vessel intervening distance was 527.8 ± 60.3 um (471–674 um). Mean minimum terminal vessel-to-vessel intervening distance was 296.7 ± 45.8 um (233–373 um). Mean maximum horizontal diameter of FAZ (superficial) was 716.17 ± 124.09 um, while mean maximum vertical diameter of FAZ (superficial) was 667.76 ± 131.28 um. Mean maximum horizontal diameter of FAZ (deep) was 823.19 ± 144.92 um, while mean maximum vertical diameter of FAZ (deep) was 794.03 ± 150.28 um. OCT-A detected different FAZ patterns; horizontally oval configuration in 32 eyes (39%), rounded configuration in 24 eyes (29.3%), pentagon configuration in 14 eyes (17.1%), and vertically oval and nonspecific configuration in 6 eyes each (7.3%). Conclusion. OCT-A could efficiently provide both quantitative and qualitative assessment of normal FAZ; such characterizations were difficult by standard FAZ assessment procedures like FFA.

Quantitative measurements with optical coherence tomography angiography in Behçet uveitis

2020 ◽  
pp. 112067212092021
Author(s):  
Hilal Eser-Ozturk ◽  
Leman Ismayilova ◽  
Ozlem Eski Yucel ◽  
Yuksel Sullu
Keyword(s):  
Optical Coherence Tomography ◽  
Patient Group ◽  
Optical Coherence Tomography Angiography ◽  
Vessel Density ◽  
Foveal Avascular Zone ◽  
Control Group ◽  
Optical Coherence ◽  
Quantitative Measurements ◽  
Capillary Vessel ◽  
Avascular Zone

Purpose The aim of this study was to evaluate the quantitative measurements obtained by optical coherence tomography angiography in patients with Behçet uveitis. Methods A total of 22 consecutive patients with Behçet uveitis and 19 age-matched healthy individuals were included in the study. Quantitative analysis of optical coherence tomography angiography images was performed. Comparisons between the patients and the control groups and correlation analysis between optical coherence tomography angiography results and age, visual acuity, duration of uveitis, central macular thickness, and fluorescein angiography scores in the patient group was performed. Results The mean superficial foveal avascular zone area was 283.040 ± 113.003 µm2 in the patient group and 254.268 ± 75.813 µm2 in the control group (p = 0.821). The mean deep foveal avascular zone area was 317.657 ± 116.225 µm2 in the patient group and 332.954 ± 94.783 µm2 in the control group (p = 0.775). The foveal avascular zone area could not be calculated in eight eyes with macular atrophy in the patient group because of unclear foveal avascular zone borders. Both superficial and deep capillary vessel density in all regions were lower in the patient group than in the control. Superior, inferior, and temporal capillary vessel density were correlated with fluorescein angiography score (Pearson’s r = –0.380, 0.392, and –0.384, p < 0.05 in superficial plexus; r = –0.357, –0.401, and –0.321, p < 0.05 in deep plexus, respectively). The foveal avascular zone area was correlated with central macular thickness in both superficial and deep plexus (r = –0.387 and –0.331, p < 0.05, respectively). Conclusion Recurrent uveitis attacks affecting the macula are associated with a decrease in capillary vessel density and expansion in the foveal avascular zone area in Behçet disease. The qualitative evaluation of the optical coherence tomography angiography findings may be more valuable in patients with macular atrophy.

Foveal avascular zone in oculocutaneous albinism

2021 ◽  
Vol 14 (5) ◽  
pp. e240208
Author(s):  
Hana A Mansour ◽  
Sami Uwaydat ◽  
Muhamad H Yunis ◽  
Ahmad M Mansour
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Oculocutaneous Albinism ◽  
Foveal Avascular Zone ◽  
Optical Coherence ◽  
Retinal Capillary ◽  
Avascular Zone ◽  
Capillary Plexus ◽  
Foveal Hypoplasia

Optical coherence tomography angiography imaging in two patients with oculocutaneous albinism, one with severe nystagmus, showed persistence of both the superficial and the deep retinal capillary plexus adding another vascular feature to the foveal hypoplasia.

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.

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