There are many causes of vision loss, but “the most common cause of vision loss I see is cataracts,” says James T. Lim, a doctor of optometry who practices in Madison, Alabama. “Most cases are due to normal aging changes. While the effects of aging are inevitable, many conditions can raise the risk of early cataracts, such as excess exposure to ultraviolet sunlight, health conditions like diabetes and high blood pressure, smoking, trauma, certain medications and poor nutrition,” he says
Research also shows cataracts and undercorrected refractive errors are among the three leading causes of treatable vision loss.
A healthy eye lens is usually clear—a cataract is a clouding of the lens. This cloudiness blocks the passage of light to the back of the eye, making images look blurry and eventually causing vision loss.
Part of the aging process, cataracts are caused by long-term exposure to UV rays, injury, disease and lifestyle choices, such as smoking and excess alcohol use. Cataracts may appear as a white, gray or yellow-brown discoloration of the lens. Correction involves surgical removal of the lens and placement of an artificial lens.
Refractive errors are a group of disorders that impair vision because the cornea can’t focus light or images onto the back of the eye correctly. These errors are more common in older populations but can occur at any age.
Myopia: Also known as nearsightedness, myopia symptoms include eye strain, headaches, squinting and difficulty seeing objects far away.
Hyperopia: With this refractive error—also known as farsightedness—your eye doesn’t bend or focus light properly to see images clearly. Distant objects may look clear, but close objects may be blurred. With significant hyperopia, vision can be blurry at any distance, near or far.
Presbyopia: This refractive error is characterized by the gradual loss of ability to see things clearly up close. It’s a normal part of aging—after age 40, you may start to notice you hold reading materials further away in order to see them clearly, which is an indication of presbyopia.
Astigmatism: An astigmatism is an imperfection in the curvature of the eye. The normal eye is round but with astigmatism, it’s shaped more like an American football. If the eye isn’t curved evenly, light rays cannot focus correctly. You may notice blurring or distortion near and far with astigmatism.
Glaucoma is a chronic, progressive condition of increased intraocular pressure on the optic nerve that may progress to permanent loss of vision. Anyone can develop glaucoma, but certain groups are at higher risk, including African Americans over the age of 40, all people over the age of 60 and people with a family history of glaucoma and diabetes.
The most effective way to treat glaucoma is to reduce your eye pressure. Treatments include medications, lasers and surgery.
This condition damages the back of the eye, or retina, causing central vision loss and distortion. Smoking and a family history of macular degeneration place you at higher risk. There are “wet” and “dry” types of macular degeneration, and treatment depends on the kind you have.
“Dry” macular degeneration is a condition in which layers of the macula become thin, atrophy (dry out) and lose their function. “Wet” macular degeneration is a less common condition in which new blood vessels grow behind the retina. They are weak and, therefore, leak fluid and blood. The leaking can cause scar tissue to form and the retina to stop functioning.
Diabetic retinopathy is a condition that damages the retina in people with high blood sugar levels. Uncontrolled blood sugar and elevated blood pressure can cause problems in the retina, such as abnormal vessel growth and bleeding. If you have diabetes or poor blood sugar control, you are at risk for diabetic retinopathy. Risk also increases the longer you’ve had diabetes.
With proper screening, good blood sugar levels, blood pressure control and early intervention, you can avoid severe vision loss.