Cerebral small vessel disease (SVD), present in 80-94% of adults over age 65 years, increases the risk of stroke by 2-fold, and dementia by 2.3-fold. There is currently no treatment to slow SVD progression. This study aims to test whether impaired cerebral and retinal vasoreactivity may serve as biomarker for SVD progression, and to evaluate the safety and efficacy of cilostazol (antiplatelet agent with vasodilatory and anti-inflammatory properties) for the treatment of SVD.