Age-Related Farsightedness May Affect More Than 1 Billion Worldwide

**trimurtulu** · 12-09-2008 04:12 PM

Age-Related Farsightedness May Affect More Than 1 Billion Worldwide

09 Dec 2008

It is estimated that more than 1 billion individuals worldwide in 2005 had presbyopia, or age-related difficulty in seeing objects nearby, with an estimated 410 million with the condition unable to perform tasks requiring near vision, according to a report in the December issue of Archives of Ophthalmology, one of the JAMA/Archives journals.

Presbyopia occurs with age, as the eye's lens loses its elasticity and ability to focus on close objects, according to background information in the article. "Although known physiology and population demographics suggest that presbyopia is common or nearly universal in people older than 65 years, direct estimates of prevalence are rare," the authors write. "The total number of people with presbyopia is primarily of interest as a precursor to the figures of greatest public health interest: the number of people with impaired vision due to uncorrected or undercorrected presbyopia and the effect on their lives."

Brien A. Holden, Ph.D., D.Sc., of the University of New South Wales, Sydney, Australia, and colleagues analyzed multiple surveys to estimate the global prevalence of presbyopia, along with the rate at which the condition is corrected and the vision impairment caused when it is not. They then used the International Data Base of the U.S. Census Bureau to extrapolate estimates for the future.

Using projections from these surveys, the researchers estimate that 1.04 billion people globally had presbyopia in 2005, 517 million of whom had no eyeglasses or inadequate eyeglasses or spectacles. Most (386 million, or 94 percent) of the individuals whose daily tasks were impaired by uncorrected presbyopia lived in the developing world.

These estimates are based on the best available information, the authors note. "More epidemiological research in presbyopia is needed to decrease the assumptions and generalizations required for a better global estimate," the authors write. "As more data become available, an increasingly accurate picture of the burden of presbyopia will emerge."

The researchers predict that the worldwide prevalence of presbyopia will increase to 1.4 billion by 2020 and 1.8 billion by 2050. "Without intervention to make spectacles more accessible, the global number of individuals who will have a disability associated with uncorrected presbyopia is predicted to grow to 563 million people by 2020," the authors conclude. "If the goal of Vision 2020 to eliminate unnecessary blindness and impaired vision, in this case due to uncorrected refractive error, is to be achieved, planning will have to include the provision of human resources, affordable spectacles and systems of delivery for these half-billion people in need."

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For Your Ready Reference:

Presbyopia -

During middle age, usually beginning in the 40s, people experience blurred vision at near points, such as when reading, sewing or working at the computer. There's no getting around it — this happens to everyone at some point in life, even those who have never had a vision problem before.
Currently an estimated 90 million people in the United States either have presbyopia or will develop it by 2014. This is generating a huge demand for eyewear, contact lenses, and surgery that can help presbyopes deal with their failing near vision.

Presbyopia Symptoms and Signs

When people develop presbyopia, they find they need to hold books, magazines, newspapers, menus and other reading materials at arm's length in order to focus properly. When they perform near work, such as embroidery or handwriting, they may have headaches or eyestrain or feel fatigued.

What Causes Presbyopia?

Presbyopia is caused by an age-related process. Presbyopia is generally believed to stem from a gradual loss of flexibility in the natural lens inside your eye.

These age-related changes occur within the proteins in the lens, making the lens harder and less elastic with the years. Age-related changes also take place in the muscle fibers surrounding the lens. With less elasticity, the eye has a harder time focusing up close. Other, less popular theories exist as well.

Tests and diagnosis

Presbyopia is diagnosed by a basic eye exam. This exam is generally administered by either an ophthalmologist or an optometrist. An ophthalmologist, who has a doctor of medicine (M.D.) degree, is a specialist trained to diagnose and manage eye disorders, including those that may require either medical or surgical treatment. An optometrist, who has a doctor of optometry (O.D.) degree, can perform many of the same services as an ophthalmologist, such as evaluating your vision, prescribing corrective lenses and diagnosing common eye disorders. In some states, optometrists also treat selected eye disorders with drugs. However, an optometrist may refer you to an ophthalmologist for more complex eye problems and for surgical procedures.

A complete eye examination involves a series of tests. Your eye doctor may use odd-looking instruments, aim bright lights directly at your eyes and request that you look through an array of lenses. Each test is necessary and allows your doctor to evaluate a different aspect of your vision.

According to the American Academy of Ophthalmology, if you don't wear glasses or contacts, have no symptoms of eye trouble and are at a low risk of developing eye disease, you should have your eyes examined at the following intervals:

• Every five to 10 years under age 40
• Every two to four years between ages 40 and 64
• Every one to two years beginning at age 65

However, if you wear glasses or contacts, have your eyes checked more often. And if you notice any problems with your vision, schedule an appointment with your eye doctor as soon as possible, even if you've recently had an eye exam. Blurred vision may suggest you need a prescription change or have another eye problem that may need evaluation and treatment.

Treatments and drugs

The goal of treatment is to compensate for the inability of your eyes to focus on nearby objects. Treatment options include wearing corrective lenses, undergoing refractive surgery or getting lens implants.

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For In-Depth details -- Please visit:

Presbyopia? - Is it different from astigmatism, nearsightedness ?