. Author manuscript; available in PMC: 2022 Jun 1.

Published in final edited form as: J Neuroophthalmol. 2020 Oct 28:10.1097/WNO.0000000000001140. doi: 10.1097/WNO.0000000000001140

Table 2.

Retinal Vascular Findings as Possible Image Biomarkers in AD spectrum

Retinal finding	Imaging modality	Advantage	Disadvantage
VD in SVP and DVP^{10,35–41,52,54}	OCTA	wide availability, no pupil dilation	no standardized analysis, requirement of clear ocular media
FAZ zone size^{36,40,41,54,56,57}	OCTA	wide availability no pupil dilation	no standardized analysis, requirement of clear ocular media
Vessel response to flicker^68,69	Dynamic vessel analyzer	dynamic analysis of vasodilatation	no wide accessibility, large vessels only
BFR^74,75	Laser Doppler retinal blood flowmetry	direct measurement of blood flow	relative measurement of all flow information, no synchronization of heartbeat, larger vessels only no wide accessibility
BFR⁷⁸	RFI	direct measurement of blood velocity and flow measurements in venules and arterioles synchronization of heat beat.	Bright visible light, pupil dilation, requirement of clear ocular media no wide accessibility
RTP⁷⁹	RFI	direct measurement of tissue perfusion direct measurement of blood velocity and flow measurements in venules and arterioles synchronization of heat beat.	Bright visible light, pupil dilation, requirement of clear ocular media no wide accessibility requirement of retinal tissue volume information

AD: Alzheimer’s disease; VD: vessel density, SVP; SVP: superficial vascular plexus; DVP; deep vascular plexus; OCTA: optical coherence tomography angiography; FAZ: foveal avascular zone; BFR: blood flow rate; RFI: retinal function imager; RTP: retinal tissue perfusion.