Reduce Risk of Developing Myopia

Here's one good reason to turn off the Wii or Game Boy: Eye experts
increasingly believe that time spent outdoors could reduce the likelihood
that children will develop myopia, or nearsightedness, a condition in
which distance vision is blurred.

"Your mother was doing the right thing when she said, 'Go outside and
play,' " says Earl Smith, dean of the College of Optometry at the
University of Houston.

Myopia is on the rise around the world. A recent study found that in
Americans ages 12 to 54, the prevalence of myopia increased 66%
between 1970 and 2000. Asia has also experienced a sharp jump in
nearsightedness in urban areas. "Nearsightedness is showing up at
younger ages and at higher progression rates," says Thomas Aller, an
optometrist based in San Bruno.
Though myopia has a strong genetic component, genes alone cannot
explain these increases.
"It's not all your family history, it's not all your outside time, it's not all
your near work," says Susan Vitale, a research epidemiologist at the
National Eye Institute of the National Institutes of Health. "All those
things work together in a complicated way that we don't really
understand yet."

"Near work" activities, such as reading and computer use, have long been
considered the most likely culprits. But recent studies indicate that the
amount of time children spend outdoors could play an important role as
well. One recent example: A 2008 study in the journal Ophthalmology
found that 12-year-olds who spent more than 2.8 hours outside per day
on average were less likely to have myopia than those who spent less
time outside, regardless of the amount of time they spent doing near
work.

One possibility is that the eyes need exposure to a certain amount of light
intensity; another is that spending time outside exposes the eyes to
objects that are consistently focused in the distance.

Optometrists and researchers are developing a new arsenal of treatments
that they hope will slow myopia's progression. These include specialized
eyeglasses and contact lenses, new types of bifocals, specialized eye drops
and contact lenses to be worn at night to reshape the cornea.
But even with these promising technologies, there is no way yet to
prevent nearsightedness or any drug to reverse it. Ultimately, scientists
hope that through better understanding of the interplay of genetics,
environmental factors and eye function, the effects of nearsightedness on
lifelong vision can be reduced.

Source: Los Angeles Times February 13, 2011
By Amanda Leigh Mascarelli, Special to the Los Angeles Times