Table 1 Studies of retinal blood flow changes in cerebral pathology
From: Retinal blood flow in critical illness and systemic disease: a review
Cerebral studies | Species | Imaging modality | Pathology | Metrics measured | Findings |
|---|---|---|---|---|---|
Frost et al. [94] | Human | Retinal photograph—Merge EyeScanner Camera | Stroke | Retinal vessels widths | Positive correlation between width of arterioles/venules and carotid disease in stroke patients |
Kwapong et al. [95] | Human | OCTA—RTVue XR Avanti SD-OCT, Optovue | PD | Retinal vessel density of SRCP and DRCP Macula and RNFL thickness | Decreased retinal microvascular density, thinner macula, macular GCIP and inferior RNFL in PD |
Querques et al. [97] | Human | DVA—Imedos Systems UG OCTA—Cirrus 5000 with Angioplex, Carl Zeiss Meditech OCT—SPECTRALIS HRA + OCT device, Heidelberg | MCI and AD | Retina artery and venous changes Perfusion density GCL thickness | DVA found arterial dilation decreased in the AD group compared with MCI and control groups and decreased vessel reaction in AD and MCI groups compared with control No differences in OCTA GCL thickness reduced in central and temporal sectors of AD patients compared with controls |
Kwa [105] | Human | Retinal photograph—Optimed, Inc MRI—1.5 T Magnetom 63 SP/4000, Siemens AG | Cerebral SVD | Retinal arterial narrowing, crossings, sclerosis, tortuosity Presence of WML or lacunar infarcts | 92% of patients with cerebral SVD had at least one retinal vascular abnormality Retinal arterial abnormalities correlated with MRI signs of cerebral SVD |
Ong et al. [127] | Human | Retinal fundus photographs | Ischaemic stroke | Retinal vasculature pattern/geometry | Ischaemic stroke patients had lower fractal dimensions, greater tortuosity and narrower arteriolar calibres compared to healthy controls |
Lee et al. [128] | Human | OCTA—Cirrus HD-OCT | Carotid Stenosis | Retinal vessel density of DVP | Vessel density of the DVP increased in both eyes, 1 month following treatment |
Jiang et al. [102] | Human | Retinal functional imager—Optical Imaging Ltd., Israel OCT—Cirrus, Carl Zeiss Meditech, CA | MCI and AD | Retinal blood flow rate/velocity GCIPL thickness | Macular blood flow rate was significantly lower in AD patients than MCI and controls, and also significantly lower in MCI patients than controls. Blood flow velocity of arterioles was significantly lower in MCI than controls GCIPL thickness was significantly reduced in AD and MCI patients than controls |
Bulut et al. [103] | Human | OCTA—RTVue XR100-2, Optovue, CA | AD | Retinal vascular density FAZ area. Choroidal thickness | AD patients had significantly lower vascular density than control group FAZ area was significantly enlarged in AD patients compared with controls Choroidal thickness was significantly lower in AD patients than controls |
Zhang et al. [104] | Human | RTVue-XR OCT Avanti System—Optovue Inc, CA | Early AD and amnestic MCI | Retinal vessel/vessel length density Adjusted flow index FAZ area RNFL thickness | Patients showed a significant decrease in the parafoveal SRCP vessel density and adjusted flow index compared with controls, but not in vessel length density No difference in FAZ area between groups No significant difference in any measures in the superficial vascular complex |
Lahme et al. [129] | Human | OCTA—RTVue XR Avanti with AngioVue | AD | Retinal and optic nerve head flow density | Flow density of the macula was significantly lower in AD patients than controls, found to be associated with vascular cerebral lesions in AD |
Abraham et al. [130] | Human | OCTA (manufacturer not specified) | At-risk MCI | Retinal vessel density | No significant association of retinal vessel density with cognitive function or risk of MCI |
Wang et al. [131] | Human | Retinal functional imaging—Optical Imaging Ltd, Israel | MS | Retinal blood flow velocity | Reduced blood flow in MS patients with and without optic neuritis compared with healthy controls |
Yilmaz et al. [132] | Human | OCTA—Nidek’s RS-3000 | MS | FAZ area Retinal vessel density | No difference in FAZ or perimeter, but lower macular vessel density in MS patients than healthy controls and in MS patients with optic neuritis compared to MS patients without optic neuritis |
Lanzillo Cennamo, & Criscuolo [133] | Human | SD-OCT—RTVue-100 OCT, Optovue Inc OCTA—Optovue Angiovue System, Optovue Inc | MS with a history of optic neuritis | Retinal vessel density RNFL and GCL thickness | RNFL and GCL thickness and vessel density were lower in the MS group (with and without optic neuritis) than the control group |
Beare and Harding [134] | Human | FFA—Topcon 50-EX, Topcon | Cerebral malaria | Retinal blood flow Tissue perfusion BRB integrity | 82% of patients with cerebral malaria had perfusion abnormalities, including capillary nonperfusion, blocked retinal vessels, retinal ischaemia, intravascular filling defects and fluorescein leakage |
Dallorto et al. [135] | Human | OCT and OCTA—RTVue XR Avanti | Pituitary adenoma with optic neuropathy | RNFL and ganglion cell complex thickness Vessel density | Vessel density, RNFL thickness and ganglion cell complex thickness were all decreased in pituitary adenoma patients with optic neuropathy compared to healthy eyes |
Suzuki et al. [136] | Human | OCTA—DRI OCT Triton Plus | Chiasmal compression band atrophy | Vessel density RNFL | Those with band atrophy showed smaller average vessel density than controls, which had a strong correlation with RNFL thinning |
Lee et al. [137] | Human | OCTA—DRI OCT Triton Plus | Pituitary tumour chiasmal compression | Vessel density RNFL and GCL thickness | Before tumour removal, vessel densities, RNFL and GCL thickness were all reduced in eyes with chiasmal compression compared with healthy controls |