Retinal detachments affect the layer of tissue that transforms light signals into messages that the optic nerve can carry to the brain. In a healthy eye, this retinal tissue lies against the back curve of the eyeball behind the gel-like vitreous, which serves as a carrier for light as it enters the eye. Sometimes, however, the vitreous exerts force on the retina and causes it to pull away from the retina.
In the most common type of retinal detachment, known as rhegmatogenous detachment, separation occurs as fluid slips under the retinal cells. This may also occur in cases of exudative detachment, which involves fluid leakage but no break of the retinal itself. Tractional detachments, common in diabetics, can develop scar tissue on the retina causing retinal elevation and visual loss. Fortunately all types of retinal detachments are treatable.