The retina is a thin membrane (like wet tissue paper) that lines the back of the eye.  Its purpose is to turn the light into a picture that can be sent to the brain through the optic nerve.  It must be attached to the back of the eye to function properly.

In front of the retina sits the vitreous humour.  It is a gelatinous, completely clear material that fills up most of the eye.  With age, it starts to liquefy and the remaining gelatinous parts move around.  Sometimes, these gelatinous parts tear the retina when they move.  This allows liquid to go through the tear and push the retina into the middle of the eye.  This is a retinal detachment.

Sagital Diagram

Retina detachments need prompt attention in order to have the best possible chance at clear vision.  Without treatment, most go on to lose significant amounts of vision.

Treatment can involve laser, gas bubbles, surgery or any combination of these options.

Symptoms of a retinal detachment include flashing lights, floaters, or loss of peripheral vision.  If you have any of these symptoms, evaluation by an eye doctor quickly is very important.