Table 3.

Studies showing evidence for the DR-CVD hypothesis.

SN	Author	Year	Imaging Device	Comorbidity	DR-CVD Link	Conclusion
1.	Liao et al. [128]	2004	Retinal imaging	hypertension, dyslipidemia, and diabetes mellitus	✓	Macro and microvascular disease support stroke prognosis.
2.	Minmoun et al. [123]	2009	Laser Doppler flowmetry	Retinal microvascular abnormalities	✓	retinopathy is correlated with white matter lesions in the brain and coronary calcification
3.	McClintic et al. [129]	2010	Retinal imaging	Type 2 diabetes	✓	Retinal vasculature abnormalities were related to coronary heart disease
4.	Liew et al. [130]	2010	Retinal imaging	CHD	✓	Fractal analysis on microvasculature predicted CHD mortality
5.	Freitas et al. [126]	2011	Color Doppler imaging	CHF	✓	Abnormalities in the optic nerve head in the eyes were related to CHF
6.	Flammer et al. [124]	2012	Color Doppler imaging	dyslipidemia, DM, or systemic hypertension	✓	CVD was found to be associated with macular degeneration and impaired autoregulation in the eyes.
7.	Seidelmann et al. [125]	2016	Retinal vessel imaging	ASCVE or heart failure (HF)	✓	Reduction in retinal arterioles and enlargement of retinal venules showed stroke and CHD
8.	Naegele et al. [127]	2017	Dynamic Retinal Vessel Analyzer	Smoking, hypertension, dyslipidemia, and diabetes mellitus	✓	In patients with CHF, the responsiveness of the retinal microvascular dilatation to flickering light was reduced.