scholarly journals The Impact of Axial Eye Growth on Foveal Avascular Zone Measurements in Children

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Rachel E. Linderman ◽  
Elizabeth Heffernan ◽  
Samantha Ferrante ◽  
Jane Bachman-Groth ◽  
Joseph Carroll
Keyword(s):  
Foveal Avascular Zone ◽  
Eye Growth ◽  
Avascular Zone ◽  
The Impact

Different effect of media opacity on automated and manual measurement of foveal avascular zone of optical coherence tomography angiographies

2020 ◽  
pp. bjophthalmol-2019-315780 ◽  
Author(s):  
Jinyu Zhang ◽  
Fang Yao Tang ◽  
Carol Cheung ◽  
Xiaolin Chen ◽  
Haoyu Chen
Keyword(s):  
Optical Coherence Tomography ◽  
Quantitative Measurement ◽  
Optical Coherence Tomography Angiography ◽  
Signal Strength ◽  
Normal Subjects ◽  
Foveal Avascular Zone ◽  
Elderly Subjects ◽  
Optical Coherence ◽  
Avascular Zone ◽  
The Impact

BackgroundOptical coherence tomography angiography (OCTA) provides not only visualisation but also quantitative measurement of foveal avascular zone (FAZ). Media opacity is common in elderly subjects with cataracts. This study aimed to investigate the impact of media opacity on automated and manual FAZ measurement.MethodsCirrus 5000 OCTA and Triton OCTA were used to image FAZ using a 3×3 mm scanning protocol from 30 eyes of 30 healthy normal subjects. Media opacity was simulated with neutral-density filters (optical density (OD): 0.10–0.48 in Cirrus 5000 and 0.15–0.51 in Triton). Signal strength (SS) and signal strength intensity (SSI) were provided by the built-in software in Cirrus 5000 and Triton, respectively. FAZ area, perimeter and circularity were measured automatically using the built-in software as well as a customised MATLAB program. FAZ metrics were also measured manually. The correlations between the OD, SS/SSI and FAZ metrics were analysed using Spearman correlation.ResultsIncreased OD significantly correlated with decreased SS/SSI (rs=−0.602 and −0.925, respectively, both p<0.001), decreased automated FAZ area (rs=−0.344 and −0.766, respectively, both p<0.001), but increased manual FAZ area in both Cirrus 5000 and Triton (rs=0.423 and 0.543, respectively, both p<0.001). Similar results were found for FAZ perimeter and circularity. There was a positive correlation between SS/SSI with the automated FAZ area but negative correlation with the manual FAZ area.ConclusionsThe effect of media opacity on quantitative measurement of FAZ is different between automated and manual measurements. Cautions must be taken when interpreting FAZ measurement in eyes with media opacity.

scholarly journals The impact of different thresholds on optical coherence tomography angiography images binarization and quantitative metrics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alessandro Arrigo ◽  
Emanuela Aragona ◽  
Andrea Saladino ◽  
Alessia Amato ◽  
Francesco Bandello ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Foveal Avascular Zone ◽  
Optical Coherence ◽  
Image Binarization ◽  
Quantitative Metrics ◽  
Avascular Zone ◽  
The Status ◽  
The Impact ◽  
Retinal Capillaries

AbstractOptical coherence tomography angiography (OCTA) provides several data regarding the status of retinal capillaries. This information can be further enlarged by employing quantitative metrics, such as vessel density (VD). A mandatory preliminary step of OCTA quantification is image binarization, a procedure used to highlight retinal capillaries on empty background. Although several binarization thresholds exist, no consensus is reached about the thresholding technique to be used. In this study, we tested thirteen binarization thresholds on a dataset made by thirty volunteers. The aim was to assess the impact of binarization techniques on: (I) detection of retinal capillaries, assessed by the calculation of overlapping percentages between binarized and original images; (II) quantitative OCTA metrics, including VD, vessel tortuosity (VT) and vessel dispersion (Vdisp); (III) foveal avascular zone (FAZ) detection. Our findings showed Huang, Li, Mean and Percentile as highly reliable binarization thresholds (p < 0.05), whereas the worst binarization thresholds were Intermodes, MaxEntropy, RenylEntropy and Yen (p < 0.05). All the thresholds variably underestimated VD metric and FAZ detection, with respect to the original OCTA images, whereas VT and Vdisp turned out to be more stable. The usage of a Fixed threshold resulted extremely useful to reduce VD and FAZ underestimations, although bound to operators’ experience.

scholarly journals Macular vessel density and foveal avascular zone parameters in patients after acute primary angle closure determined by OCT angiography

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kangcheng Liu ◽  
Huizhuo Xu ◽  
Haibo Jiang ◽  
Hua Wang ◽  
Pingbao Wang ◽  
...  
Keyword(s):  
Early Stage ◽  
Normal Subjects ◽  
Vessel Density ◽  
Foveal Avascular Zone ◽  
Angle Closure ◽  
Acute Primary Angle Closure ◽  
Primary Angle Closure ◽  
Circularity Index ◽  
Avascular Zone ◽  
And Control

Abstract This study analyzed the optical coherence tomography angiography (OCTA) macular parameters in primary angle-closure glaucoma (PACG) patients after acute primary angle closure (APAC) episodes. Thirty-three patients with 33 APAC eyes and 33 primary angle closure suspect (PACS) eyes and 33 age-matched normal subjects (controls) were enrolled. Macular vessel density (VD) in central, inner, outer and full regions and foveal avascular zone (FAZ) parameters (area, perimeter and circularity index) were compared between APAC, PACS, and control eyes. For resolved APAC eyes, the VD in each macular region was significantly lower than that in control eyes, with less central and inner macular VD than PACS eyes. The central macular VD was significantly lower in PACS eyes than in controls. There was no difference in FAZ area and perimeter between APAC, PACS, and control eyes. FAZ circularity was highest in control eyes, followed by PACS eyes, and lowest in APAC eyes. The AUC, sensitivity and specificity of FAZ circularity were 0.944, 93.9% and 84.8%, respectively, in APAC eyes and 0.881, 84.8% and 81.8%, respectively, in PACS eyes. Therefore, FAZ circularity had the best discrimination capability for detecting both APAC and PACS eyes. Macular assessment with OCTA could provide an accurate early-stage diagnostic tool for PACG.

Convexity shape constraints for retinal blood vessel segmentation and foveal avascular zone detection

2020 ◽  
Vol 127 ◽  
pp. 104049
Author(s):  
José Escorcia-Gutierrez ◽  
Jordina Torrents-Barrena ◽  
Margarita Gamarra ◽  
Pedro Romero-Aroca ◽  
Aida Valls ◽  
...  
Keyword(s):  
Blood Vessel ◽  
Vessel Segmentation ◽  
Foveal Avascular Zone ◽  
Retinal Blood Vessel ◽  
Shape Constraints ◽  
Blood Vessel Segmentation ◽  
Avascular Zone

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.

OCT-A PICTURE OF THE EYEFOOL IN CHRONIC RENAL FAILURE

2021 ◽  
Vol Special issue (3) ◽  
pp. 50-53
Author(s):  
M. Kh. Karimova ◽  
◽  
U.F. Mavlyanova ◽  
A.А. Abdushukurova ◽  
Z.T. Matkarimov ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Clinical Manifestations ◽  
Foveal Avascular Zone ◽  
Microcirculatory Bed ◽  
Microvascular Changes ◽  
Avascular Zone ◽  
The World ◽  
Working Age ◽  
Quantitative Changes

Renal retinopathy is a severe late microvascular complication of CRF and one of the causes of blindness in the world among people of working age. OCT-A makes it possible to detect microvascular changes in the retina even in the absence of clinical manifestations of renal retinopathy on the fundus. Markers of changes in the microcirculatory bed of the retina in renal retinopathy arequalitative and quantitative changes in the foveal avascular zone and a decrease in the density of the capillary network, which increase with the progression of the disease.Keywords:Renal retinopathy, CRF, OCT, angiography, retinal changes

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