Variability of Foveal Avascular Zone Metrics Derived From Optical Coherence Tomography Angiography Images. Transl Vis Sci Technol 2018 Sep;7(5):20
Date
10/04/2018Pubmed ID
30280005Pubmed Central ID
PMC6166903DOI
10.1167/tvst.7.5.20Scopus ID
2-s2.0-85056655072 (requires institutional sign-in at Scopus site) 57 CitationsAbstract
PURPOSE: To characterize sources of inter- and intrasubject variability in quantitative foveal avascular zone (FAZ) metrics.
METHODS: Two 3×3-mm optical coherence tomography angiography scans (centered on the fovea) were acquired in both eyes of 175 subjects. An image of the superficial plexus was extracted from each scan and segmented twice by a single observer. Four quantitative FAZ morphology metrics (area, axis ratio, acircularity, major horizontal axis angle) were calculated, and a variance components analysis was performed.
RESULTS: Mean (±SD) age was 27.9 ± 11.9 years, and 55% were female. Area had the largest amount of variance resulting from intersubject differences (93.1%). In contrast, there was large interocular variance for axis ratio, acircularity, and major horizontal axis angle (55.0%, 53.7%, 70.7%, respectively), though only axis ratio showed significant asymmetry between fellow eyes (P < 0.05). Neither repeated images from the same eye nor repeated segmentation on the same image were significant sources of variance.
CONCLUSIONS: Metrics of FAZ morphology show excellent repeatability and reliability. Excluding FAZ area, there was a high amount of variance attributed to interocular differences for the other FAZ metrics; therefore, the fellow eye should not be considered a control for FAZ studies when using these metrics.
TRANSLATIONAL RELEVANCE: Vision scientists must be prudent when choosing FAZ metrics, as they display varying degrees of within-subject differences relative to between-subject differences. It seems likely that different metrics will be best suited for different tasks, such as monitoring small changes over time within a single subject or assessing whether a given FAZ is abnormal.
Author List
Linderman RE, Muthiah MN, Omoba SB, Litts K, Tarima S, Visotcky A, Kim JE, Carroll JAuthors
Joseph J. Carroll PhD Director, Professor in the Ophthalmology and Visual Sciences department at Medical College of WisconsinSergey S. Tarima PhD Associate Professor in the Data Science Institute department at Medical College of Wisconsin
