Squint at Computer Screen: Eye Risk?
Study Shows Squinting May Lead to Dry Eye
Dec. 2, 2005 - The more you squint at a computer screen, the more you may be
putting your eyes at risk.
A new study shows the more people squint at a computer screen, the less they
blink, and the more they reported symptoms like eye strain, dryness,
irritation, and tearing.
Researchers found squinting at a computer screen halves the normal number of
times a person blinks per minute, which could lead to an irritating but
treatable condition called dry eye.
"People tend to squint when they read a book or a computer display, and
that squinting makes the blink rate go way down," says researcher James
Sheedy, professor of optometry at Ohio State University, in a news release.
"Blinking rewets the eyes. So if your job requires a lot of reading or
other visually intense work, you may be blinking far less than normal, which
may cause eye strain and dry eye."
Blink Before Continuing
In the study, published in Optometry and Vision Science,
researchers had 10 college students with normal vision squint at a computer
screen placed two feet in front of them while cameras and electrodes recorded
how often they blinked.
In five different tests, researchers measured how often the students blinked
while at rest or engaged in deliberate squinting at various increments, from
barely squinting to eyes closed about halfway.
The results showed even a slight degree of squinting cut blink rates in
half, from about 15 blinks a minute to 7.5 blinks a minute. That rate was cut
to just four blinks per minute when the students were squinting at the highest
Researchers say squinting serves two purposes: it improves eyesight by
defining objects that are out of focus, and it cuts down on brightness from
sources of glare.
Squinting often occurs as an involuntary response, and researchers say
people working at a computer may not even realize they are squinting. They say
more research is needed to determine if involuntary squinting affects blink
rates as drastically as voluntary squinting, as measured by this study.
But these results suggest that squinting may increase the risk of eye strain
and dry eye. Dry eye is usually treatable with over-the-counter lubricating eye