There are many causes of vision loss, but “the most common cause of vision loss that I see is cataracts,” says James T. Lim, a doctor of optometry who practices in Madison, Alabama. âMost cases are due to the normal changes in aging. Although the effects of aging are inevitable, many conditions can increase the risk of early cataracts, such as excessive exposure to ultraviolet rays from the sun, health problems like diabetes and high blood pressure, smoking, trauma , some medications and a poor diet, âhe says.
Research also shows that cataracts and under-corrected refractive errors are among the top three causes of treatable vision loss.
A healthy lens is usually clear – a cataract is clouding of the lens. This cloudiness blocks the passage of light to the back of the eye, causing images to appear blurry and possibly resulting in loss of vision.
Part of the aging process, cataracts are caused by long-term exposure to UV rays, injuries, illnesses, and lifestyle choices, such as smoking and heavy drinking. Cataracts can appear as a white, gray, or yellow-brown discoloration of the lens. Correction involves the surgical removal of the lens and the placement of an artificial lens.
Refractive errors are a group of disorders that impair vision because the cornea cannot properly focus light or images on the back of the eye. These errors are more common in older populations, but can occur at any age.
Myopia: Also known as nearsightedness, symptoms of nearsightedness include eye strain, headache, strabismus, and difficulty seeing distant objects.
Hyperopia: With this refractive error, also known as hyperopia, your eye does not bend or focus light properly to see images clearly. Distant objects may appear clear, but near objects may be blurry. With severe hyperopia, vision can be blurry at any distance, near or far.
Presbyopia: This refractive error is characterized by the gradual loss of the ability to see things clearly up close. This is a normal part of aging – after 40, you may begin to notice that you are holding reading materials further away so that you can see them clearly, which is an indication of presbyopia.
Astigmatism: Astigmatism is an imperfection in the curvature of the eye. The normal eye is round but with astigmatism it is more shaped like an American football. If the eye is not bent evenly, the light rays cannot focus properly. You may notice blur or distortion near and far with astigmatism.
Glaucoma is a chronic, progressive disease characterized by increased pressure in the eye on the optic nerve which can progress to permanent loss of vision. Anyone can develop glaucoma, but certain groups are at higher risk, including African Americans over 40, all over 60, and people with a family history of glaucoma and diabetes.
The most effective way to treat glaucoma is to reduce eye pressure. Treatments include drugs, lasers, and surgery.
This condition damages the back of the eye or the retina, causing central vision loss and distortion. Smoking and a family history of macular degeneration put you at a higher risk. There are âwetâ and âdryâ types of macular degeneration, and treatment depends on which type you have.
“Dry” macular degeneration is a condition in which the layers of the macula become thinner, atrophied (dry out) and lose their function. âWetâ macular degeneration is a less common condition in which new blood vessels develop behind the retina. They are weak and therefore leak fluid and blood. The leak can cause scar tissue to form and the retina to stop.
Diabetic retinopathy is a condition that damages the retina in people with high blood sugar. Uncontrolled blood sugar and high blood pressure can cause problems with the retina, such as abnormal blood vessel growth and bleeding. If you have diabetes or if you have poor blood sugar control, you are at risk for diabetic retinopathy. The risk also increases the longer you have had diabetes.
With proper screening, good blood sugar, blood pressure control, and early intervention, you can prevent severe vision loss.