Foveal avascular zone area measurements with optical coherence tomography angiography in patients with nanophthalmos

Demircan, Ali; Yeşilkaya, Ceren; Altan, Çiğdem; Alkın, Zeynep; Yaşa, Dilek; Aygıt, Ebru Demet; Bektasoglu, Damla

doi:10.1038/s41433-018-0236-7

Cited by 6 publications

(3 citation statements)

References 20 publications

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“…The FAZ is related to the visual acuity of the patient in different diseases, as could be diabetic retinopathy (DR) and retinal vein occlusion [3]- [5], among others [6]. In the same line, there are clinical studies that demonstrate that the FAZ area varies with healthy and pathological subjects [7], [8], as well as with different degrees of the same disease [9]. Additionally, it has also been discovered that the size of the FAZ region changes with some risk habits, as occurs, for example, with tobacco consumption [10].…”

Section: Introductionmentioning

confidence: 99%

Modeling, Localization, and Segmentation of the Foveal Avascular Zone on Retinal OCT-Angiography Images

2020

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The Foveal Avascular Zone (FAZ) is a capillary-free area that is placed inside the macula and its morphology and size represent important biomarkers to detect different ocular pathologies such as diabetic retinopathy, impaired vision or retinal vein occlusion. Therefore, an adequate and precise segmentation of the FAZ presents a high clinical interest. About to this, Angiography by Optical Coherence Tomography (OCT-A) is a non-invasive imaging technique that allows the expert to visualize the vascular and avascular foveal zone. In this work, we present a robust methodology composed of three stages to model, localize, and segment the FAZ in OCT-A images. The first stage is addressed to generate two FAZ normality models: superficial and deep plexus. The second one uses the FAZ model as a template to localize the FAZ center. Finally, in the third stage, an adaptive binarization is proposed to segment the entire FAZ region. A method based on this methodology was implemented and validated in two OCT-A image subsets, presenting the second subset more challenging pathological conditions than the first. We obtained localization success rates of 100% and 96% in the first and second subsets, respectively, considering a success if the obtained FAZ center is inside the FAZ area segmented by an expert clinician. Complementary, the Dice score and other indexes (Jaccard index and Hausdorff distance) are used to measure the segmentation quality, obtaining competitive average values in the first subset: 0.84 ± 0.01 (expert 1) and 0.85 ± 0.01 (expert 2). The average Dice score obtained in the second subset was also acceptable (0.70 ± 0.17), even though the segmentation process is more complex in this case.

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Section: Introductionmentioning

confidence: 99%

Modeling, Localization, and Segmentation of the Foveal Avascular Zone on Retinal OCT-Angiography Images

2020

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“…Studies involving mostly pre‐term children have attributed a reduced or absent FAZ and increased foveal thickness to subnormal postnatal development of the foveal area of the macula 5 . However, it is currently unclear if a reduced or absent FAZ will lead to future problems 14 …”

Section: Introductionmentioning

confidence: 99%

“… 5 However, it is currently unclear if a reduced or absent FAZ will lead to future problems. 14 There are also other conditions such as nanophthalmos that can lead to a small FAZ. In addition, characteristics of the FAZ can also be affected by myopia (larger FAZ) 15 or sex (larger among females).…”

Section: Introductionmentioning

confidence: 99%

All retinas are not created equal: Fovea‐to‐macula thickness ratio and foveal microvasculature in healthy young children

Demir

Hovsepian

Pagels

et al. 2022

Ophthalmic Physiologic Optic

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Markers for the relationships between structural and microvasculature measures given by optical coherence tomography angiography are necessary to increase the diagnostic and prognostic value of this technique. The aim of this study was to investigate relationships between structural and microvasculature measures around the fovea in healthy eyes of healthy children. Methods:Observational cross-sectional study involving children aged 8-17 years, born at full-term, with no eye disease. The better of two 3 × 3 mm macular scans obtained with a Cirrus 5000HD-OCT was analysed. Images were corrected for lateral magnification errors. Vessel density and perfusion were measured with ImageJ/Fiji software for the superficial capillary plexus. Structural measures including foveal and macular thicknesses were performed manually. Results:The sample included 86 participants, 51 (59%) females. Mean age was 12.4 years (SD = 2.5); mean best-corrected acuity was −0.10 logMAR (SD = 0.09); mean refractive error was +0.59 D (SD = 1.3) and mean axial length was 23.1 mm (SD = 0.86). Mean area of the foveal avascular zone (AFAZ) was 0.20 mm 2 (SD = 0.88); median fovea-to-macula thickness ratio (FMTR) was 0.63 (IQR = 0.08); mean central vessel density was 12.42 mm −1 (SD = 2.78) and mean central perfusion was 38.66% (SD = 3.83). AFAZ was correlated with central vessel density (p < 0.001), perfusion (p < 0.001), foveal thickness (p < 0.001) and FMTR (p < 0.001). Central vessel density was correlated with foveal thickness (p < 0.001) and FMTR, (p = 0.01). Central perfusion was correlated with foveal thickness (p < 0.001) and FMTR, (p = 0.003). Conclusion:In this study, foveal thickness, FMTR and foveal microvasculature measurements were correlated. Clinicians need to be aware that shallow foveal pits and persistent foveal microvasculature are likely to occur in optical coherence tomography angiography images. In healthy eyes from healthy children, an atypical high FMTR and a small AFAZ may be associated with incomplete foveal development. The mechanism and functional implications of this remain unknown.

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Swept source-OCT and swept source-OCT angiography findings in posterior microphthalmos

et al. 2019

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Foveal avascular zone area measurements with optical coherence tomography angiography in patients with nanophthalmos

Cited by 6 publications

References 20 publications

Modeling, Localization, and Segmentation of the Foveal Avascular Zone on Retinal OCT-Angiography Images

Modeling, Localization, and Segmentation of the Foveal Avascular Zone on Retinal OCT-Angiography Images

All retinas are not created equal: Fovea‐to‐macula thickness ratio and foveal microvasculature in healthy young children

Swept source-OCT and swept source-OCT angiography findings in posterior microphthalmos

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