This project is an exploratory study, using enhanced depth imaging with the new SPECTRALIS OCT, designed to examine choroidal and microvascular retinal structure in patients with hypertension, chronic kidney disease (CKD), and in age and sex matched healthy controls. The study is non-invasive and takes only a few seconds to acquire these complex images. The Centre, where the images will be captured and where image analysis systems are located, is on the Royal Infirmary of Edinburgh (RIE) site close to the RIE outpatient clinics, making recruitment easy.