scholarly journals Acircularity and Circularity Indexes of the Foveal Avascular Zone in High Myopia

2021 ◽  
Author(s):  
Helong Piao ◽  
Yue Guo ◽  
Haowei Zhang ◽  
Mi Sun Sung ◽  
Sang Woo Park
Keyword(s):  
Axial Length ◽  
High Myopia ◽  
Major Axis ◽  
Foveal Avascular Zone ◽  
Strongly Correlated ◽  
Circularity Index ◽  
Avascular Zone ◽  
The Mean ◽  
Size And Morphology ◽  
Specific Influence

Abstract We explored the association between foveal avascular zone (FAZ) parameters and high myopia using optical coherence tomography angiography (OCTA). To evaluate the specific influence of high myopia on the FAZ, we divided 106 eyes of 106 patients into quartiles based on the axial length. The upper quartile was then defined as the high myopia group (n = 27), while the lower quartile was the non-high myopia group (n = 26). The FAZ parameters of these two groups were then retrospectively compared to investigate variations in FAZ size and morphology. The mean axial length and spherical equivalent were 23.96 ± 0.94 mm and -2.27 ± 1.58 diopters in the non-high myopia group and 27.42 ± 0.36 mm and -8.12 ± 2.14 diopters in the high myopia group, respectively. The areas of superficial and deep FAZ, perimeters of deep FAZ, major axis lengths of deep FAZ, minor axis lengths of superficial and deep FAZ were significantly larger in eyes with high myopia than in eyes with non-high myopia (P < 0.05). Linear regression analyses showed that no significant correlation was observed between FAZ areas and acircularity and circularity index of FAZ in non-high myopia group, conversely, FAZ areas strongly correlated with acircularity and circularity index of FAZ in high myopia group. We found that An increase in the FAZ area in highly myopic eyes was accompanied by a significant variation in FAZ acircularity and circularity indexes. Further research should address whether these findings are associated with future disease development in highly myopic eyes.

scholarly journals Acircularity and circularity indexes of the foveal avascular zone in high myopia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helong Piao ◽  
Yue Guo ◽  
Haowei Zhang ◽  
Mi Sun Sung ◽  
Sang Woo Park
Keyword(s):  
Significant Variation ◽  
High Myopia ◽  
Optical Coherence Tomography Angiography ◽  
Major Axis ◽  
Minor Axis ◽  
Foveal Avascular Zone ◽  
Strongly Correlated ◽  
Regression Analyses ◽  
Lower Quartile ◽  
Avascular Zone

AbstractThis study explored the association between foveal avascular zone (FAZ) parameters and high myopia using optical coherence tomography angiography. We divided 106 eyes of 106 patients into quartiles based on the axial length. The upper quartile was then defined as the high myopia group (n = 27), while the lower quartile was the non-high myopia group (n = 26). The areas and minor axis lengths of superficial and deep FAZ, the perimeters and major axis lengths of deep FAZ were significantly larger in eyes with high myopia than in eyes with non-high myopia (P < 0.05). Inversely, the subfoveal choroidal thickness was significantly thinner in eyes with high myopia than in those with non-high myopia. Linear regression analyses showed that no significant correlation was observed between FAZ areas and acircularity and circularity indexes of FAZ in non-high myopia group. Conversely, FAZ areas strongly correlated with acircularity and circularity indexes of FAZ in high myopia group. We found that an increase in the FAZ area in highly myopic eyes was accompanied by a significant variation in FAZ acircularity and circularity indexes. Further research should address whether these findings are associated with future disease development in highly myopic eyes.

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.

Unmeasurable small size superficial and deep foveal avascular zone in nanophthalmos: the Collaborative Nanophthalmos OCTA Study

2018 ◽  
Vol 103 (8) ◽  
pp. 1173-1178 ◽  
Author(s):  
Ahmad M Mansour ◽  
Michael W Stewart ◽  
Salma W Yassine ◽  
Carl-Joe Z Mehanna ◽  
Antonio Marcelo B Casella ◽  
...  
Keyword(s):  
Axial Length ◽  
Fundus Autofluorescence ◽  
Cross Sectional Study ◽  
Foveal Avascular Zone ◽  
Measurement Tool ◽  
Cross Sectional ◽  
Avascular Zone ◽  
Capillary Plexus ◽  
The Mean ◽  
Spearman’S Correlation

AimTo study the macular structure and vasculature in consecutive nanophthalmic eyes using optical coherence tomography angiography.MethodsThis is a prospective, multicentre, cross-sectional study of patients with nanophthalmos (one or both eyes). The superficial and deep foveal avascular zones (FAZ) were measured both manually and with the machine’s built-in automated measurement tool. Correlations between best corrected visual acuity (BCVA), central macular thickness (CMT) and subfoveolar choroidal thickness (SFCT) were calculated.ResultsSixty-five eyes of 35 subjects (16 men and 19 women) with a mean age of 37.4 years were analysed. The mean±SD of refractive error was 14.3±3.2 dioptres, axial length was 16.4±1.6 mm, CMT was 410.2±128.3 µm and SFCT was 450.1±108.3 µm. FAZ was unmeasurable small size in both the superficial and deep capillary plexus in all eyes, along with tortuosity of the superficial foveal capillaries and large vessels. Foveal folds were present in 29 eyes. Disc drusen was detected in 27 eyes and was absent in 31 eyes, while fundus autofluorescence was positive in 17 and negative in 24 eyes. BCVA varied from 20/20 to 20/800, with a mean of 20/76. Using Spearman’s correlation, logarithm of the minimum angle of resolution BCVA correlated negatively with axial length (r=−0.30; p=0.015).ConclusionsFAZ attenuation, capillary tortuosity, foveal folds and thickened subfoveal choroid characterise the nanophthalmic macula. These findings may result from a redundant retina and the absence of apoptotic foveolar retraction because of developmental arrest of the optic vesicle after closure of the embryonic fissure.

scholarly journals Quantitative assessment and determinants of foveal avascular zone in healthy volunteers

2021 ◽  
Vol 49 (5) ◽  
pp. 030006052110149
Author(s):  
Lijun Zhou ◽  
Fengqun Wang ◽  
Ling Wang ◽  
Peiyang Shen ◽  
Yi Cao ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Axial Length ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Univariate Analysis ◽  
Anterior Chamber Depth ◽  
Foveal Avascular Zone ◽  
Cross Sectional ◽  
Avascular Zone ◽  
The Mean

Objectives To evaluate the foveal avascular zone (FAZ) area in healthy volunteers using optical coherence tomography angiography (OCTA) and identify factors that influence the FAZ. Methods This single-center cross-sectional study included 526 eyes of 263 healthy volunteers who underwent macular scanning by Zeiss OCTA. A linear mixed model was used to investigate the effects of systemic factors (age, sex, blood pressure, height, and weight) and ocular factors (intraocular pressure, biometric parameters, and central macular thickness) on FAZ. Results In total, 520 eyes of 262 healthy volunteers were included in the analysis. The mean volunteer age was 38.59 ± 22.03 years (range, 5–84 years); 124 volunteers were male (47.33%) and 138 volunteers were female (52.67%). The mean FAZ area was 0.30 ± 0.03 mm2 (95% confidence interval [CI], 0.29–0.31 mm2). Univariate analysis showed that FAZ area was associated with age (β = 0.0011), anterior chamber depth (β = −0.0513), and axial length (β = −0.0202). Multivariate analysis showed that FAZ area was negatively correlated with axial length (β = −0.0181). Conclusions The mean FAZ area in healthy volunteers, measured using Zeiss OCTA, was 0.30 ± 0.03 mm2. Furthermore, FAZ area was negatively associated with axial length; this relationship should be considered in clinical practice.

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.

scholarly journals Glaucomatous Macular Vasculature: A Quantitative Analysis

2020 ◽  
Vol 9 (3) ◽  
pp. 185-197
Author(s):  
Pedro Arede ◽  
Joanna Przezdziecka-Dolyk ◽  
Fabian Debowy ◽  
Jacek Olszewski ◽  
Carla Fernandes ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Structural Changes ◽  
Open Angle Glaucoma ◽  
Major Axis ◽  
Foveal Avascular Zone ◽  
Control Group ◽  
Equivalent Diameter ◽  
Optical Coherence ◽  
Fiber Layer ◽  
Avascular Zone

Background: The aim of this study was to evaluate the characteristics of the macular vessel density (VD) and the foveal avascular zone (FAZ) in glaucoma quantitatively using the optical coherence tomography angiography (OCT-A). Methods: Twenty-five eyes of 13 patients with primary open angle glaucoma (POAG) and 12 eyes of 6 healthy participants were enrolled retrospectively. Functional visual field (VF) and structural Spectral-Domain optical coherence tomography (SD-OCT) Retinal Nerve Fiber Layer Thickness (RNFLT) were assessed in all participants. OCT-A was performed on a fovea centered, 15x10 degrees, macular region. OCT-A scans were processed with MATLAB software and automatically graded to define FAZ parameters. The parafoveal VD in the superficial and deep retinal vascular plexus (SVP and DVP) was analyzed by quadrant and circular segmented zones. Results: Foveal Avascular Zone -Major Axis Length (p=0.02), Area (p=0.04), Equivalent Diameter (p=0.04) and Perimeter (p=0.04) were significantly larger in glaucoma than the control group. Regarding SVP and DVP, the average macular total VD were lower in glaucoma patients compared to the control group (p<0.01; p<0.01). Additionally, the inner circular region (p=0.04; p<0.01 respectively for SVP and DVP) and all quadrants except for North had a lower VD in glaucoma group compared to the control group. Assessment of the total VD successfully predicted RNFLT (p<0.001) and was significantly associated with the probability of glaucoma (p=0.009). Conclusion: OCT-A parameters, namely the FAZ morphology and the macular VD, were associated with glaucomatous functional and structural changes. The macular VD showed a considerable diagnostic value. It may be a modern biomarker, representing microvascular network disruption of the macular perfusion in glaucoma.

scholarly journals Association of foveal avascular zone with the metamorphopsia in epiretinal membrane

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hideki Shiihara ◽  
Hiroto Terasaki ◽  
Shozo Sonoda ◽  
Naoko Kakiuchi ◽  
Hidetaka Yamaji ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Superficial Layer ◽  
University Hospital ◽  
Foveal Avascular Zone ◽  
Service Unit ◽  
Corrected Visual Acuity ◽  
Avascular Zone ◽  
The Mean ◽  
The Relationship ◽  
Best Corrected Visual Acuity

Abstract This study was to investigate the relationship between the metamorphopsia and foveal avascular zone (FAZ) parameter in eyes with epiratinal membrane (ERM). We studied patients with an ERM visited retinal service unit at the Kagoshima University Hospital or Shirai Hospital. The best-corrected visual acuity (BCVA), and the degree of metamorphopsia by M -CHARTS™ were evaluated. The 3 × 3 mm optical coherence tomography angiography (OCTA) images of the superficial layer were obtained. Area (mm2), the circularity, eigen value were calculated using ImageJ software. The relationship between visual function, such as best corrected visual acuity (BCVA) and metamorphopsia, and FAZ parameters were studied by Pearson’s correlational coefficient. Fifty-four eyes of 51 patients (24 men and 27 women) with an ERM were studied. The mean age of the patients was 69.6 ± 8.20 years. The mean BCVA and metamorphopsia score was 0.31 ± 0.29 logMAR units and 0.49 ± 0.42. There was no significant relationship between BCVA and FAZ parameters. While, metamorphopsia score was significantly and negatively correlated with all of FAZ parameters (area R = − 0.491, P < 0.001; circularity R = − 0.385, P = 0.004; eigenvalue ratio R = − 0.341; P = 0.012). Multiple regression analysis showed the FAZ area was solely and significantly correlated with metamorphopsia score (β − 0.479, P < 0.001). The size but not the shape of the FAZ was significantly correlated with the degree of metamorphopsia suggesting that it could be an objective parameter of metamorphopsia in ERM patients.

scholarly journals One-Year Analysis of the Refractive Stability, Axial Elongation and Related Factors in a High Myopia Population after Implantable Collamer Lens Implantation

2021 ◽  
Author(s):  
Xun Chen ◽  
Zhi Chen ◽  
Huamao Miao ◽  
Xuanqi Wang ◽  
Xiaoying Wang ◽  
...  
Keyword(s):  
Axial Length ◽  
High Myopia ◽  
Implantable Collamer Lens ◽  
Related Factors ◽  
Axial Elongation ◽  
Adult Age ◽  
Corrected Distance Visual Acuity ◽  
Length Changes ◽  
The Mean ◽  
One Year

Abstract Purpose: To investigate the refractive stability, axial length changes and their related factors in a high myopia population after Implantable Collamer Lens (ICL) implantation.Methods: This prospective study included 116 eyes of 116 patients divided into several groups based on the spherical equivalent refractive error (SE)—SE > -6D, -12 ≤ SE < -6D and SE < -12D groups—and axial length (AL)—AL < 28mm and AL ≥ 28mm groups. The uncorrected and corrected distance visual acuity, refraction, axial length and intraocular pressure were followed for 1 year.Results: SE changed from -11.53 ± 5.25D preoperatively to -0.33 ± 0.70D at 1 week, and further changed to -0.48 ± 0.77D at 1 year after ICL implantation, with average progression being -0.15 ± 0.37D from 1 week to 1 year after surgery. Axial length changed from 27.95 ± 2.33mm preoperatively to 27.98 ± 2.36mm 1 year after surgery, with an average axial elongation of 0.03 ± 0.12mm. The mean axial elongation rate was 0.05mm/year in the SE < -12D group, being significantly faster than the other SE groups (P < 0.05); it was 0.06mm/year in the AL ≥ 28mm group, being significantly faster than the AL < 28mm group (P < 0.05).Conclusion: Patients with high myopia and long axial length showed a continuous myopic progression and axial elongation at an adult age after ICL surgery, especially those with myopia higher than -12.0D and AL longer than 28.00mm.

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.

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