The quantitative measurements of foveal avascular zone using optical coherence tomography angiography in normal volunteers

Abstract

PurposeTo provide normative data of foveal avascular zone (FAZ) and thickness.MethodsIn this cross-sectional study both eyes of each normal subject were scanned with optical coherence tomography angiography (OCTA) for foveal superficial and deep avascular zone (FAZ) and central foveal thickness (CFT) and parafoveal thickness (PFT).ResultsOut of a total of 224 eyes of 112 volunteers with a mean age of 37.03 (12–67) years, the mean superficial FAZ area was 0.27 mm2, and deep FAZ area was 0.35 mm2 (P < 0.001), with no difference between both eyes. Females had a larger superficial (0.32 ± 0.11 mm2 versus 0.23 ± 0.09 mm2) and deep FAZ (0.40 ± 0.14 mm2 versus 0.31 ± 0.10 mm2) (P < 0.001) than males. By multivariate linear regression analysis, in normal eyes, superficial FAZ area varied significantly with the gender, CFT, and deep FAZ. Deep FAZ varied with the gender and CFT.ConclusionThe gender and CFT influence the size of normal superficial and deep FAZ of capillary network.

Variability of Foveal Avascular Zone Metrics Derived From Optical Coherence Tomography Angiography Images

“… 18 – 20 However, as with all laterally based measurements in retinal images, individual differences in ocular magnification and axial length need to be corrected in order to accurately compare area measurements between subjects or across studies. 1 , 21 The need to measure axial length, as well as the large variation of area seen in normal individuals, 1 – 3 , 19 , 22 – 25 makes it difficult to use area as a measure to compare small changes associated with disease progression between subjects or for identifying an FAZ as “abnormal.” While these limitations are less important when assessing repeatability of OCTA during a single visit, 26 they represent important barriers to comparing data across different studies and populations.…”

Optical coherence tomography angiography findings in malignant hypertensive retinopathy

“…As in the study by Falavarjani et al, OCTA also can perform vascular calibration measurements, but no specific study has used it for measuring hypertension (5) . Ghassemi et al reported that superficial FAZ measured 0.22 ± 0.08 mm 2 and deep FAZ was 0.31 ± 0.11 mm 2 in normal eyes in their study (6) . In our case, superficial FAZ was 0.147 mm 2 on the first day and 0.151 mm 2 at 6 months in the right eye, and it was 0.193 mm 2 on the first day and 0.178 mm 2 at 6 months in the left eye.…”

Verändert sich die foveale avaskuläre Zone beim Glaukom?

“…Die eingangs bereits beschriebenen Vergrößerungen der FAZ bei vaskulären Netzhauterkrankungen konnten auch mittels der OCT-A bestätigt werden, z. T. bereits bevor klinisch sichtbare Veränderungen auftraten [8,36,37]. Einflussfaktoren, die die Fläche bei Gesunden verändern können, sind u. a., wie auch bereits bei der Fluoresceinangiografie gemessen, ein zunehmendes Alter [38], das Geschlecht [39 -41], zentrale foveale Dicke [39] und die Achslänge [41].…”

“…Choi et al hatten mehr Männer in beiden Gruppen eingeschlossen, wir mehr Frauen. Nach Ghassemi et al [39] haben Frauen im oberflächlichen und tiefen Plexus eine größere FAZ-Fläche (p < 0,001) als Männer. Demzufolge hätte man bei den Ergebnissen der Arbeitsgruppe Choi et al kleinere FAZ-Flächen als bei uns erwartet.…”