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Thursday, February 14, 2008

A new vision for the aging eyes of America

Vision impairment and eye diseases are major public health problems among older Americans. More than 3.4 million Americans aged 40 years or older are either blind or visually impaired.1 Eighteen percent of Americans aged 70 years and older self-reported blindness in one or both eyes or some other trouble seeing.2 Older Americans are also disproportionately affected by vision impairment, as people aged 65 years of age or older make up 12.8% of the U.S. population but account for 30% of all cases of visually impairment.3 As people age, they face a vast array of health disorders that can potentially lead to disability. One of the most feared disabilities among older adults is a vision disability. This fear is justifiable when one considers that loss of vision often correlates with a loss of independence. Compromises in eye function cannot easily be overcome and affect people�s ability to drive, read, watch television, or simply attend to common household or personal tasks. Reduced vision in this select population has been shown to result in social isolation, increased risk of falling and resultant hip fractures, depression, family stress, and ultimately a greater tendency to be disabled or die prematurely.4-6 In 2003, the direct and indirect costs of visual disorders and disabilities in the United States was approximately 68 billion dollars; these costs continue to escalate.7 As discussed below, the four most common causes of vision impairment and blindness in the United States are age-related macular degeneration (AMD), diabetic retinopathy, cataracts, and glaucoma. Age-related Macular Degeneration (AMD) is the leading cause of irreversible vision loss among older adults. AMD results from a breakdown of the central retinal tissue leading to leakage and a subsequent loss of central vision. Those affected often lose their ability to read, see facial details, watch television, and drive. Peripheral vision however, remains intact, so individuals with AMD are still able to move about on their own. According to the National Eye Institute, 1.8 million Americans aged 50 years or older have AMD and another 7.3 million people are at substantial risk for developing AMD due to early retinal changes in the macular area.8 Diabetic retinopathy is a common complication of diabetes. Elevated blood sugar damages the retinal blood vessels causing them to breakdown, leak, or become blocked. Over time, this causes retinal hemorrhage and impaired oxygen delivery to the retina that can lead to the growth of abnormal vessels. These new vessels are fragile and can easily break, causing permanent vision loss. One of 12 people with diabetes aged 40 years and older has vision-threatening diabetic retinopathy.8 cataracts are a clouding of the eye lens most often caused by aging. The lens is responsible for focusing the images onto the retina, and thus a clouding of the lens can result in diminished vision as well as increased sensitivity to glare. Over half of all Americans aged 65 years and older have cataracts.3 Glaucoma is a progressive disease that damages the eye�s optic nerve. It is the eye�s optic nerve that is responsible for carrying the retinal image to the brain so any disruption in this transmission can result in irreversible blind spots or field loss that over time can lead to total blindness. A view of the optic nerve during a dilated eye exam combined with visual field testing, intraocular pressure testing (IOP) and other tests can often reveal damage at an early stage, thus providing opportunity for treatment. It is important to note that IOP should never be used as a sole diagnostic indicator. Among Americans aged 40 years or older, 2.2 million have glaucoma and another 1.1 million are unaware of having the disease.8 For this reason glaucoma is often referred to as the �silent thief of sight.� Glaucoma is twice as common among black older adults as it is among whites. The silver lining to these sobering statistics is that half of all blindness today can be prevented. Most people with low vision can now benefit from vision rehabilitation, environmental modifications, and assistive devices that can maximize their residual vision and help them maintain an independent, productive life. Early detection and timely treatment; however, is the essential element to this healthy equation.
Age related eye diseases most often have no early symptoms or clear warning signs, and therefore require a dilated examination by an optometrist or ophthalmologist on a periodic basis. The dilated component of the examination in which drops are instilled in the eyes, allows the doctor a better view of the lens, optic nerve, and retina as well as other internal aspects of the eye. A comprehensive eye exam may also detect early signs of age related systemic diseases such as; cardiovascular diseases, connective tissue diseases, thyroid disorders, and malignancies. The American Academy of Ophthalmology recommends an eye exam every one to two years for people over age 65 and the American Optometric Association recommends that persons aged 61 years and older have a yearly eye examination. Both professional provider organizations stipulate that patients with risk factors for eye disease may require examination more often. As an example, individuals diagnosed with diabetes should have, at minimum, yearly dilated eye exams but may require exams more often. A recent study using Medicare data found that older adults who visit an eye doctor regularly have a lower probability of a vision related decline in reading ability and in developing low vision and blindness. In addition to frequent eye examinations; we encourage people to make healthful lifestyles choices that have been shown to facilitate eye health such as not smoking, protecting ones eyes from ultra violet rays, chemicals and projectiles, and eating a diet rich in antioxidan

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