The retina is the light-sensitive layer at the back of the eye that converts light images into nerve impulses that are relayed to the brain to produce sight. When the retina separates from the deeper layers of the eyeball that normally support and nourish it, the retina is said to be detached. Without this nourishment and support, the retina does not function properly, and this can cause a variety of visual symptoms. For example, if the retina detaches near the macula, the part of the eye that is responsible for the center of the visual field (reading for instance), then there may be a sudden, significant blurring or loss of vision. However, if the area of detachment is closer to the outer edges of the retina, then the visual loss may be more like a curtain being drawn over one side of the visual field (the "curtain effect"). Other symptoms of retinal detachment may include floating shapes in the field of vision or brief flashes of light.
Although there are several types of retinal detachment, the most common one starts when a tear or hole develops in the retina, and some of the gel-like substance that fills the inside of the eye (vitreous fluid) leaks through the opening. Eventually, the leaking vitreous fluid gets behind the retina, separating the retina from other layers of the eye.
The retinal tear that triggers a retinal detachment sometimes is caused by trauma. More often, it is caused by a change in the gel-like consistency of the vitreous fluid that can occur as a part of aging. This age-related change can occur unpredictably in older people, and there is no way to prevent it. Once this type of retinal detachment develops and causes symptoms, it can progress to total blindness if it is not repaired promptly.
In the United States, retinal detachment is a relatively uncommon condition, affecting only one of every 10,000 Americans each year. However, there are certain groups who have an unusually high risk of developing this problem, including:
People who have had cataract surgery — Up to 3% of people who have had cataract surgery eventually develop a detached retina, making retinal detachment the most serious post-surgical complication of cataract treatments. The high rate of retinal detachments after cataract surgery may be related to the vitreous fluid inside the eye becoming watery instead of gel-like after surgery. If there has been a complication at the time of cataract surgery especially if the posterior capsule of the human lens has torn and there has been loss of the vitreous, jelly retinal complications especially detachment is even more common.
Severely nearsighted people — These people often are nearsighted because they have an eyeball that is unusually long. The elongated shape creates more stress between the vitreous fluid and the surface of the retina.
People who have had blunt trauma to the eye or penetrating eye injuries
In many cases, the more risk factors a person has, the higher the risk of retinal detachment. For example, a very nearsighted person who also undergoes cataract surgery probably will have a higher risk of retinal detachment than someone who has cataract surgery and is not nearsighted. Overall, the risk of retinal detachment increases the older you get, and men are about 50% more likely to develop the problem than women.
People with diabetes also have a higher risk of a different type of retinal detachment as a complication of diabetic retinopathy, a family of retinal disorders thought to be related to abnormal or erratic blood sugar levels.