The Definition, Rationale, and Effects of Thresholding in OCT Angiography

PURPOSE: To examine the definition, rationale, and effects of thresholding in OCT angiography (OCTA). DESIGN: A theoretical description of OCTA thresholding in combination with qualitative and quantitative analysis of the effects of OCTA thresholding in eyes from a retrospective case series. PARTICIPANTS: Four eyes were qualitatively examined: 1 from a 27-year-old control, 1 from a 78-year-old exudative age-related macular degeneration (AMD) patient, 1 from a 58-year-old myopic patient, and 1 from a 77-year-old nonexudative AMD patient with geographic atrophy (GA). One eye from a 75-year-old nonexudative AMD patient with GA was quantitatively analyzed. MAIN OUTCOME MEASURES: A theoretical thresholding model and a qualitative and quantitative description of the dependency of OCTA on thresholding level. RESULTS: Due to the presence of system noise, OCTA thresholding is a necessary step in forming OCTA images; however, thresholding can complicate the relationship between blood flow and OCTA signal. CONCLUSIONS: Thresholding in OCTA can cause significant artifacts, which should be considered when interpreting and quantifying OCTA images.
Macula Vision Research Foundation
National Institutes of Health (U.S.) (NIH R01-EY011289-29A)
National Institutes of Health (U.S.) (R44-EY022864)
National Institutes of Health (U.S.) (R01-CA075289-16)
United States. Air Force. Office of Scientific Research (AFOSR FA9550-15-1-0473)
United States. Air Force. Office of Scientific Research (FA9550-12-1-0499)
Praevium Research Inc.
Massachusetts Lions Clubs
Samsung (Firm) (Scholarship)