There are three types of retinal detachment .
Rhegmatogenous retinal detachment is the most common type of detachment. It is caused by holes or breaks in the retina called retinal tears. A retinal tear allows fluid from the middle of the eye to pass through the tear and settle under the retina. As the fluid builds up under the retina, it pushes the retina away from the layer beneath it.
The most frequent cause of retinal tears is posterior vitreous detachment (PVD). PVD is a normal part of aging, in which the vitreous gel separates from the retina. PVD is usually harmless, but sometimes the vitreous gel can pull so hard that it tears the retina. Retinal tears occur most often on the sides (periphery) of the retina, because the vitreous gel is attached to the retina most strongly in those areas. If eye fluid moves through the tear and builds up under the retina, the retina may come off the back of the eye.
Retinal tears often do not lead to retinal detachment. But retinal tears that occur with new symptoms (such as floaters, flashes of light, or other visual disturbances) are much more likely to progress to detachments. A retinal detachment also may be more likely to occur if you have other things that increase your risk-for example, if you are nearsighted or if you have had recent cataract surgery.
Traction retinal detachment occurs when scar tissue or other abnormal tissue grows on the surface of the retina, pulling the retina away from the layer beneath it. This does not cause a specific tear or break in the retina.
Exudative retinal detachment occurs when blood or fluid from the middle layer of tissue that forms the eyeball (choroid) flows into the space under the retina and separates the retina from the layer beneath it. The detachment does not involve tears in the retina or traction from the vitreous.
Exudative retinal detachment is most often a complication of other diseases or conditions. These can include severe macular degeneration, eye tumors, inflammation in the choroid or the retina, or severe high blood pressure.