The retina is the nerve layer that lines the inside of the back of the eye. It senses light and sends images on to the brain. When the retina is separated from the layer beneath the retina that gives it nourishment, called the choroids, this is called retinal detachment. The retina does not work when it is detached. This is a very serious problem and, if untreated, almost always leads to blindness.
Most retinal detachments result from a hole or tear that develops in the retina. The tear allows fluid to leak through and get under the retina, separating it from the layer beneath, much like a blister. The most common reason for a break in the retina is when the vitreous or clear jelly that fills the middle of the eye shrinks and pulls on the retina. This may occur in one or more places.
After the development of the retinal tear, fluid passes through, lifting the retina off like wallpaper peeling off a wall. Many times this occurs spontaneously, especially in older persons in whom there may be weak spots from natural aging. Several conditions increase the possibility of retinal detachment. These include: