Cystoid macular oedema is a painless condition which affects the macula – the central part of the retina (Figure 1.1 and 1.2). This condition occurs when fluid collects in the tissue at the back of the eye, including the area responsible for our central vision. This accumulation of multiple pockets of fluid as cysts in the macular area, is known as cystoid macular oedema.
The light-sensitive layer of retinal cells converts light into electrical signals which are then sent to the brain where they are turned into the images we see. A brilliant network of tiny blood vessels constantly supplies blood to the retina.