Quantitative vs. Qualitative Assessment for Foveal Avascular Zone in Diabetic Retinopathy

Abstract

Diabetic retinopathy (DR) is one of the leading causes of blindness, with macular ischemia being a central factor in its progression. The foveal avascular zone (FAZ), a region of the macula devoid of blood vessels, is commonly used as a marker of macular ischemia in diabetic retinopathy. Traditionally, fluorescein angiography (FA) has been used to qualitatively assess changes in the FAZ. However, with the advent of optical coherence tomography (OCT) and newer technologies like optical coherence tomography angiography (OCTA), both qualitative and quantitative assessments of the FAZ have become possible. While qualitative assessments involve subjective evaluations of the FAZ's shape and size, quantitative assessments measure parameters such as the FAZ's area, perimeter, and circularity, offering a more objective, consistent, and reproducible approach. This paper reviews the advantages and limitations of both assessment methods, discussing their applicability in monitoring the progression of diabetic retinopathy and their relationship to macular ischemia. Quantitative assessments provide more accurate and standardized measurements, which are essential for tracking disease progression and evaluating treatment outcomes.

Keywords: Foveal avascular zone (FAZ), diabetic retinopathy, quantitative assessment, qualitative assessment, macular ischemia, fluorescein angiography (FA), optical coherence tomography (OCT).