How Fireworks May Harm the Eyes
Scratches From Explosive Material, Not Blast Pressure, Behind Most Firework-Related Eye Injuries
July 3, 2012 -- Putting on protective eyewear before setting off fireworks may help prevent common firework-related injuries.
A new study suggests exposure to flying debris from firework explosions may be a bigger factor in eye injuries than the force of the blasts themselves.
Researchers found that scratches on the cornea from projected explosive material were the most common injury in their small study. The cornea is the transparent tissue layer that covers the eye.
"The eye is the most frequently injured body part [related to use of fireworks] and accounts for more than 2,000 injuries annually," researcher Vanessa Alphonse of Virginia Tech-Wake Forest University in Blacksburg, Va., and colleagues write in the Journal of the American Medical Association.
"Although it is suggested that the pressure wave caused by explosions (i.e., blast overpressure) can cause eye injury ... there is no clear evidence to support this," they write.
How Fireworks May Hurt Eyes
In their study, researchers looked at whether blast overpressure or projected material causes firework-related eye injuries.
Researchers exposed human cadaver eyes to 18 blasts at three different distances -- ranging from about 8-and-a-half inches to just under 3 inches -- using 10-gram charges of gunpowder to simulate fireworks.
Minor grain-sized abrasions on the cornea were the only injuries found following the blasts.
High-speed video showed the injuries were caused by unspent explosive material being projected into the eye.
Although pressure within the eye increased the closer it was to the explosion, the risk of injury was extremely low (less than or equal to 0.01%).
Researchers say the results offer new information about how fireworks can cause eye injuries that could help in designing more effective protective equipment and firework laws.