Since vascular impairment has been hypothesized to play a role in several ocular diseases including glaucoma, diabetic retinopathy and age-related macular degeneration, the non-invasive assessment of ocular blood flow has received more and more attention. Despite the many advances that have been made in the last 30 years, there is still no gold standard for the evaluation of blood flow in humans available and sophisticated and expensive equipment is required. This article aims to review the different techniques available today for the assessment of ocular blood flow. Furthermore the advantages and the possible limitations of the techniques are discussed.