What Causes Hypofluorescence?

Hypofluorescence

    • Reduced visibility of underlying retinal or choroidal circulation due to a barrier located anterior to that circulation. Common causes of blocked fluorescence include heme, scar tissue and hyperpigmentation.

    • The blocking material should become apparent when comparing the IVFA scan with a colour or red-free photo.

    • Anterior segment material

    • Vitreous material

    • Inner retinal material

    • Subretinal material

    • Deep retinal material

    • A filling defect causes hypofluorescence due to reduced perfusion - meaning less fluorescein is reaching the vasculature.

    • If there is a complete absence of perfusion, the hypofluorescence will persist throughout the whole angiogram. If there is only partially reduced perfusion, there will be delayed filling.

    • Arterial defect

    • Venous defect

    • Capillary bed defect

    • Combination defect

    • Optic pit and coloboma

    • Vascular occlusion around the optic disc

    • Optic atrophy

    • Physiological

    • Posterior ciliary artery obstruction or carotid obstruction

    • Absence of choroidal vascular tissue

Figure informed by: Rabb MF, Burton TC, Schatz H, Yannuzzi LA. Fluorescein angiography of the fundus: a schematic approach to interpretation. Survey of ophthalmology. 1978 May 1;22(6):387-403.