What are the risk factors for developing a retinal detachment?
Studies have shown that the incidence of retinal detachments caused by tears in the retina is fairly low, affecting approximately one in 10,000 people each year. Many retinal tears do not progress to retinal detachment. Nevertheless, many risk factors for developing retinal detachments are recognized, including certain diseases of the eyes (discussed below), cataract surgery, and trauma to the eye. Retinal detachments can occur at any age. They occur most commonly in younger adults (25 to 50 years of age) who are highly nearsighted (myopic) and in older people following cataract surgery.
Which diseases of the eyes predispose to the development of a retinal detachment?
Lattice degeneration of the retina is a type of thinning of the outside edges of the retina, which occurs in 6%-8% of the general population. The lattice degeneration, so-called because the thinned retina resembles the crisscross pattern of a lattice, often contains small holes. Lattice degeneration is more common in patients with nearsightedness (myopia). This tendency to lattice degeneration occurs because myopic eyes are larger than normal eyes and, therefore, the peripheral retina is stretched more thinly. Fortunately, only about 1% of patients with lattice degeneration go on to develop a retinal detachment.
High myopia (greater than 5 or 6 diopters of nearsightedness) increases the risk of a retinal detachment. In fact, the risk increases to 2.4% as compared to a 0.06% risk for a normal eye at age 60. (Diopters are units of measurement that indicate the power of the lens to focus rays of light.) Cataract surgery or other operations of the eye can further increase this risk in patients with high myopia.
Patients taking certain eye drops have an increased risk of developing a retinal detachment. Pilocarpine (Polocarp 2 or 4%), which for many years has been a mainstay of therapy for glaucoma, has long been associated with retinal detachment. Moreover, by constricting the pupil, pilocarpine makes the diagnostic exam of the peripheral retina more difficult, possibly leading to a delay in the diagnosis.
Patients with chronic inflammation of the eye (uveitis) are at increased risk of developing retinal detachment.