Healthy eye retina. Fluorescein angiogram of the retina of a healthy eye. Fluorescein dye has been injected into the bloodstream of the eye retina; this dye fluoresces green when blue light is shone onto it. Here, the light green outline of major retinal blood vessels is seen. Blood vessels emerge through the retina from the optic disc (far left) which is the blind spot of the eye. At centre is the darker macula, an area of retina where there is greatest acuity of vision and where light is focused. The retina lines the inside of the eye; it has light-sensitive cells responsible for detecting visual images.