Cardiovascular disease is the most common disease in the western world. Ischaemic heart disease and cerebrovascular disease together account for a half of all deaths. Optometrists will encounter many patients with some form of cardiovascular disease in their clinical practice. In many cases, the optometrist will be the first to detect it and appropriate referral will be necessary. This article, the fifth in a series published in Optometry in Practice, deals with the basic pathology of cardiovascular disease and covers some of the common diseases that the optometrist may encounter