Reliability of foveal avascular zone metrics automatically measured by Cirrus optical coherence tomography angiography in healthy subjects

  • Aidi Lin
  • Danqi Fang
  • Cuilian Li
  • Carol Y. Cheung
  • Haoyu ChenEmail author
Original Paper



To investigate the reliability of the foveal avascular zone (FAZ) metrics automatically measured using Cirrus optical coherence tomography angiography (OCTA) embedded algorithm compared to human manual measurement.


Thirty-five eyes of 35 healthy subjects were enrolled and scanned four times continuously on Zeiss Cirrus HD-OCT 5000. The FAZ metrics (area, circularity and perimeter) of the superficial capillary plexus were measured automatically using the embedded tool and manually measured by the two independent observers using ImageJ. The repeatability of the four scans within all methods of measurements was calculated. The agreement of the manual vs automated measurement was also analyzed.


The repeatability of the automated algorithm was only poor to moderate (intraclass correlation coefficients [ICCs] for the area, perimeter and circularity were 0.600, 0.405 and 0.221, respectively) while the repeatability of the manually measured FAZ area and perimeter was good [([ICCs] ranged from 0.845 to 0.877) except the circularity (ICC = 0.538 to 0.608)]. The ranges of 95% limits of agreement between the manual measurements by the two observers were only 20% to 31% of those of automated–manual agreement. The Cirrus inbuilt algorithm obviously outlined the border of FAZ wrongly in 22.9% cases.


Caution should be taken when using the automated measurement results of FAZ metrics in Cirrus OCTA, because of the low repeatability and poor agreement compared with the manual measurement.


Optical coherence tomography angiography Foveal avascular zone Reliability Metrics Automated algorithm Healthy subjects 


Author contributions

HC contributed to the study conception and design. Material preparation, data collection and analysis were performed by AL, DF and CL. The first draft of the manuscript was written by AL. HC and CYC revised the manuscript. All authors read and approved the final manuscript.


This study is supported by the Grant for Key Disciplinary Project of Clinical Medicine under the Guangdong High-level University Development Program (002-18119101).

Compliance with ethical standards

Conflict of interest

All authors declare that they have no conflict of interest.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the Institutional Review Board of Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong and with the 1964 Helsinki Declaration and its later amendments.

Informed consent

Informed consent was obtained from all individual participants included in the study.


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Copyright information

© Springer Nature B.V. 2019

Authors and Affiliations

  1. 1.Joint Shantou International Eye CenterShantou University and the Chinese University of Hong KongShantouChina
  2. 2.Department of Ophthalmology and Visual SciencesThe Chinese University of Hong KongHong KongChina

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