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Jeff Dahl

Is Technology Destroying Our Eyesight?

December 17, 2009 02:00 PM
by James Sullivan
The prevalence of nearsightedness among people in the U.S. has increased dramatically in recent decades. What role have computers, cell phones and other “nearwork” played in this change?

Nearsightedness on the Rise in U.S.

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A study conducted by the National Eye Institute found that nearsightedness, or myopia, has increased 66 percent since the 1970s. The prevalence of myopia found in a population sample from 1971-1972 was 25 percent, compared with 41.6 percent from 1999-2004. The study did not examine the underlying causes of the increase, but experts believe factors including heredity, a lack of outdoor light and “nearwork,” could be contributing.

Nearwork includes activities like reading and texting, and some experts believe excessive, or exclusive nearwork can affect the development of children’s eyes. More research is needed before doctors can say exactly what impact nearwork has on eyesight.

Full text of the study, “Increased Prevalence of Myopia in the United States Between 1971-1972 and 1999-2004,” is available for free on the Archives of Ophthalmology’s Web site.

Background: Studying myopia

In a 1994 New York Times article, Jane Brody analyzed the question of whether myopic eyes are born or made in her piece “In Debate on Myopia’s Origins The Winner Is: Both Sides?” In her assessment of these two theories—that which argues nearsightedness to be genetically determined, and that which says it is acquired over the course of one’s life—she concludes, “myopia, the inability to bring distant objects into clear view, appears to develop in response to various environmental influences most often in children who are somehow genetically predisposed to this visual aberration.”

Computer users have long suspected a connection between myopia and computer use. Two years after her piece on myopia’s origins, Brody followed up by reviewing the impact of computers on eyesight. She specifically discussed a condition called computer vision syndrome.

“With images on a computer screen fast supplanting the printed word, complaints about vision-related problems like eyestrain, blurry vision, headaches and neck aches are multiplying rapidly. Millions of people, from preschool ages on, who work or play the day away on video display terminals are suffering needlessly, experts say.”

A recent epidemic of myopia plaguing Japan and Singapore was theorized to have genetic roots. However this theory was debunked by a 2004 study published in The American Journal of Human Genetics. Rachel Nowak for New Scientist discussed the resultant belief that lifestyle differences, such as more time spent indoors in front of screens is to blame. “There is little doubt about at least one underlying cause. Children now spend much of their time focusing on close objects, such as books and computers.”

But why wouldn’t this increased ocular activity strengthen eyes? When one strains their arms and legs, the muscles adapt, resulting in increased strength. Nowak says, “To compensate [for nearwork] the eyeball is thought to grow longer. That way less effort is needed to focus up close, but the elongated eye can no longer focus on distant objects.”

Despite all the speculation, no connections between nearwork and permanent myopia have been firmly established through research. Though a 2007 study explored a possible link between permanent myopia and a condition called nearwork-induced transient myopia (NITM). NITM is “defined as the short-term myopic far point shift immediately following a sustained near visual task.”

Opinion: A question of causality

Skeptics argue that the increase in use of computers and texting over the last few decades does not necessarily mean these activities are the underlying cause of the surge in nearsightedness. Dr. Cary Silverman, writing on The LASIK Blog, said, “The story further went on that there is a genetic predisposition to develop myopia and suggests that close work may be a contributing factor, however, there is no scientific proof if this linkage. Adding the fact that there are over 110 billion text messages sent annually just clouds the issue. Many more people eat sushi today than in the 1970’s, maybe this is the cause of myopia development?!?”

A 2003 study at Ohio State University, published in Investigative Ophthalmology & Visual Science, found heredity to be the primary cause of myopia, and suggested that environmental factors play a minor role in the development of nearsightedness.

Reference: Nearsightedness

Mayo Clinic offers readers a primer on nearsightedness, or myopia. It includes information about causes, symptoms, diagnosis, treatment and prevention.
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