Vision loss is among the top 10 most prevalent disabilities in the United States, according to the Centers for Disease Control and Prevention. As of 2015, about 4 million Americans were either blind or visually impaired due to conditions that can’t be corrected with glasses or contacts, and another 8 million were impaired due to lack of glasses or contacts.
Most common conditions
Cleveland Clinic identifies these as the five most common vision problems.
Commonly known as "nearsightedness" or "farsightedness," in the medical community, this type of visual impairment stems from "refractive errors." These occur when the eyeball, cornea, or lens is slightly misshapen, which affects how light bends and lands on the retina and therefore how the brain perceives images. An astigmatism is also a type of refractive error. Age and family history are risk factors for this type of visual impairment, which can usually be treated with glasses, contacts, or laser surgery.
Age-related macular degeneration
This is the top cause of vision loss among Americans 60 and older. It occurs as the light-sensing cells in the center of the retina degrade with age. Smoking is a major risk factor for this condition, while high blood pressure and high HDL cholesterol are also believed to increase risk. It has no cure, but exercise, nutritional changes and some drug and laser therapies can slow its progression.
The most common eye disease worldwide, glaucoma occurs when too much fluid builds up in the eyeball. This causes pressure on the optic nerve, compromising peripheral vision first and then central vision. African Americans and Hispanic or Latino individuals are at greater risk for glaucoma. Age and family history are also risk factors, regardless of ethnicity. There is no known cure, but prescription eye drops, laser treatments, and surgery can keep it from getting worse.
This occurs when the lens of the eye becomes clouded, due to age or trauma, preventing some light from getting through. The condition first manifests in poor night vision. Age, diabetes, smoking, and excessive alcohol consumption are all risk factors. Exposure to UV rays, which can be prevented by wearing sunglasses, is another risk factor. Cataracts are reversible with a common surgery in which the clouded lens is replaced by a clear artificial lens. But due in part to lack of access to medical care, cataracts remain the leading cause of vision loss worldwide, accounting for more than 50% of all blindness.
This condition occurs when there is damage to the blood vessels connected to the retina, caused by Type 1 or Type 2 diabetes. This condition may cause blurred vision, painful pressure, and “floaters.” Management of diabetes through diet, exercise, and in some cases insulin is key to preventing it.
Less common conditions that cause visual impairment
A genetic condition that is most well known for causing lack of pigment in the hair and skin, albinism also affects the eyes, causing low vision and light sensitivity. There is no medical treatment, but sunglasses and magnifiers can help those with the condition adapt.
Commonly known as “crossed eyes,” this condition occurs when a person cannot align both eyes, due to reduced muscle control. Up to 5% of children have some degree of strabismus, but it is usually treatable and even reversible, with non-surgical vision therapy or surgery.
Retinitis pigmentosa (RP)
An inherited condition that causes severe vision loss over time, RP usually first shows up as night blindness in childhood or early teens. There is no cure, but treatments like vitamin A supplements and retinal implants can slow the progression.