Axial length variation impacts on retinal vessel density and foveal avascular zone area measurement using optical coherence tomography angiography

Sampson, Danuta M.; Gong, Peijun; An, Di; Menghini, Moreno; Hansen, Alex; Mackey, David A.; Sampson, David D.; Chen, Fred K.

doi:10.1117/12.2270134

Cited by 4 publications

(6 citation statements)

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“…[24][25][26][27][28][29][30] In addition, the area of the FAZ is dependent on the axial length of the eye that needs to be compensated for by software but such software is embedded in only some of the OCTA instruments. 31,32 Several recent studies including our study have quantified the shape of the FAZ, and the results showed that variances of the shape of the FAZ were not as large as that of the FAZ area. In DR and glaucoma, it was reported that shape of the FAZ was helpful in understanding the pathological processes.…”

Section: Introductionmentioning

confidence: 58%

“…Thus, the true FAZ area is still difficult to be determined. 31,33 This may be an underlying problem of the current studies of the FAZ.…”

Section: Discussionmentioning

confidence: 99%

“…24 -30 In addition, the area of the FAZ is dependent on the axial length of the eye that needs to be compensated for by software but such software is embedded in only some of the OCTA instruments. 31,32…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Shape of Foveal Avascular Zone by Optical Coherence Tomography Angiography in Eyes With Branch Retinal Vein Occlusion

Shiihara

Terasaki

Sonoda

et al. 2018

Journal of VitreoRetinal Diseases

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To determine the relationship between morphological parameters of the foveal avascular zone (FAZ) in the optical coherence tomography angiographic (OCTA) images and the best-corrected visual acuity (BCVA) in branch retinal vein occlusion (BRVO). Methods: This was a retrospective cross-sectional study. Eyes with BRVO without apparent macular edema were studied. The superficial FAZ in 3 Â 3 mm OCTA images were delineated manually. The size and shape, the circularity and axial ratio, of the FAZ were determined, and the values were compared to that of the controls. The correlation of these parameters with the BCVA was analyzed. Results: The mean FAZ area was larger in BRVO eyes than in controls, but the larger size was not correlated with the BCVA (BRVO, 0.49 + 0.12 mm 2 ; control, 0.38 + 0.12 mm 2 ; P ¼ .135). The axial ratio of the BRVO eyes was significantly larger than that of controls (P < .001). The axial ratio was significantly correlated with BCVA (R ¼ .382, P ¼ .050). Although the circularity was significantly smaller in the BRVO eyes than that in controls (P < .001), it was not significantly correlated with the BCVA. Conclusion: The shape of the FAZ would be a more appropriate parameter than the size in determining BCVA in eyes with BRVO.

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Section: Introductionmentioning

confidence: 58%

“…Thus, the true FAZ area is still difficult to be determined. 31,33 This may be an underlying problem of the current studies of the FAZ.…”

Section: Discussionmentioning

confidence: 99%

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Evaluation of Shape of Foveal Avascular Zone by Optical Coherence Tomography Angiography in Eyes With Branch Retinal Vein Occlusion

Shiihara

Terasaki

Sonoda

et al. 2018

Journal of VitreoRetinal Diseases

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“…All analyses were corrected for the magnification effect. Littmann formula was used to calculate true image size, as described previously (19,20).…”

Section: Ophthalmic Examinationmentioning

confidence: 99%

“…With the elongation of AL, the scanning area increases, resulting in optical amplification effect. Measurements performed with OCT have inherent errors when the scale of retinal image is not corrected for AL of each eye (20,21). In order to correct the optical amplification effect of OCT measurement, Littmann formula was used to calculate true image size make the results more accurate.…”

Section: Ophthalmic Examinationmentioning

confidence: 99%

Assessment of choroidal vascularity and choriocapillaris blood perfusion in Chinese preschool-age anisometropic hyperopic amblyopia children

Wang

Hua

et al. 2022

Front. Pediatr.

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PurposeTo determine the macular and peripapillary area choroid microstructure parameters of hyperopic anisometropic amblyopia eyes and compare to fellow and age-matched control eyes. To assess the correlation between the axial length (AL), choroidal thickness (CT) and choroid microstructure parameters.MethodsThis cross-sectional comparative, non-interventional study involved 52 hyperopic anisometropic amblyopia children and 48 age-matched heathy controls. 52 eyes with hyperopic anisometropic amblyopia and 48 age-matched control eyes were studied. The peripapillary and subfoveal CT were determined. The total choroidal area (TCA), luminal area (LA), and stromal area (SA) of the subfoveal and peripapillary choroid were measured. In addition, the correlation between the AL, CT and choroid microstructure parameters were calculated.ResultsThe peripapillary and subfoveal CT of the amblyopic eyes was significantly thicker than the fellow and control eyes (all P < 0.05). The subfoveal and peripapillary choroidal SA, LA and TCA of the amblyopic eyes were significantly increased than that of the fellow and control eyes (all P < 0.05). The choroidal vascularity index (CVI) values of the amblyopic eye were significantly different among the three groups (P < 0.05). There was a statistically significant negative correlation between AL and subfoveal CT (SFCT), LA and TCA levels (P < 0.001, P = 0.039, P = 0.027, respectively). Spherical equivalent (SE) was positive correlated with SFCT, LA and TCA levels (P = 0.456, 0.229 and 0.240, respectively; all P < 0.05). There was a statistically significant positive correlation between SFCT, SE, LA, SA, TCA and CVI levels (all P < 0.05).ConclusionThe subfoveal and peripapillary CT of amblyopic children abnormally increased and correlated with shorter AL and higher SE. The choroidal structure of the amblyopic eyes was different from the fellow and control eyes, the hyperopic anisometropic amblyopic eyes had significantly thicker sub-foveal choroid, higher LA, SA, and TCA. AL and CT affect choroidal structure and vascular density. Choroidal blood flow may be increased in amblyopic eyes. The larger LA, SA, TCA, and lower CVI were characteristic of the amblyopic eye.

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Megahertz multi-parametric ophthalmic OCT system for whole eye imaging

Hu,

Feng,

Long

et al. 2024

Biomed. Opt. Express

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An ultrahigh-speed, wide-field OCT system for the imaging of anterior, posterior, and ocular biometers is crucial for obtaining comprehensive ocular parameters and quantifying ocular pathology size. Here, we demonstrate a multi-parametric ophthalmic OCT system with a speed of up to 1 MHz for wide-field imaging of the retina and 50 kHz for anterior chamber and ocular biometric measurement. A spectrum correction algorithm is proposed to ensure the accurate pairing of adjacent A-lines and elevate the A-scan speed from 500 kHz to 1 MHz for retinal imaging. A registration method employing position feedback signals was introduced, reducing pixel offsets between forward and reverse galvanometer scanning by 2.3 times. Experimental validation on glass sheets and the human eye confirms feasibility and efficacy. Meanwhile, we propose a revised formula to determine the “true” fundus size using all-axial length parameters from different fields of view. The efficient algorithms and compact design enhance system compatibility with clinical requirements, showing promise for widespread commercialization.

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Axial length variation impacts on retinal vessel density and foveal avascular zone area measurement using optical coherence tomography angiography

Cited by 4 publications

References 0 publications

Evaluation of Shape of Foveal Avascular Zone by Optical Coherence Tomography Angiography in Eyes With Branch Retinal Vein Occlusion

Evaluation of Shape of Foveal Avascular Zone by Optical Coherence Tomography Angiography in Eyes With Branch Retinal Vein Occlusion

Assessment of choroidal vascularity and choriocapillaris blood perfusion in Chinese preschool-age anisometropic hyperopic amblyopia children

Megahertz multi-parametric ophthalmic OCT system for whole eye imaging

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