Too Much Summer Sun May Hurt Eyes Later
May 10, 2004 -- Spending too much time outdoors in the summer
sun may raise the risk of a common sight-robbing disease later in life,
according to a new study.
Researchers found that people who spent a lot of time in the
summer sun in their teens, 30s, and after age 40 were twice as likely to
develop an early form of age-related macular degeneration than those who stayed
out of the sun.
However, the study also suggests that protective measures, such
as wearing a hat and sunglasses, can dramatically reduce some of those
additional sun-related risks.
Age-related macular degeneration is the leading cause of vision
loss in older people, and few treatments are available for the disease. The
condition leads to an abnormal growth of blood vessels and opaque deposits on
the retina, the light-sensitive layer of cells located at the back of the eye.
It also causes an increase in the amount of pigment in the retina.
The precise cause of the disease is unknown, but a combination
of genetic and environmental factors is thought to play a role.
Summer Sunlight Linked to Macular Degeneration
In the study, researchers looked at the association between
sunlight exposure and the 10-year risk of age-related macular degeneration
among a large group of adults aged 43 to 86 years who were first examined
between 1988 and 1990 as a part of the Beaver Dam Eye Study.
The results appear in the May issue of The Archives of
Researchers found that people who spent more than five hours a
day in the summer sun in their teens, 30s, and after age 40 were more than
twice as likely to develop early age-related macular degeneration compared with
those who reported spending less than two hours per day of sunlight during the
In addition, those who got five or more hours per day of summer
sun were more than three times as likely to develop increased retinal pigment,
a condition commonly associated with age-related macular degeneration.
But the study showed wearing hats or sunglasses at least half
of the time reduced the risk of developing deposits on the retina by 50% among
those who reported the highest sun exposure levels.
The study also found that people who had more than 10 severe
sunburns in their youth were two and a half times more likely to develop an
increase in pigments found in the retina.
No relationships were found between UVB exposure, winter
leisure time spent outdoors, skin sun sensitivity, or the number of bad
sunburns experienced by the time the study began and the 10-year risk of
abnormal blood vessel formation or plaque deposits in the retina.