Fireworks are a Fourth of July celebration staple. But if party planning were left up to eye doctors, they'd likely say to leave the explosions to the professionals.
Even with the myriad warnings issued each year on the risk of eye injury of at-home fireworks around the holiday, eyes are still the second most common injured part of the body. There were 1,100 eye injuries treated in the same one-month period in 2011, according to Prevent Blindness America.
But exactly what type of eye injuries are caused by fireworks? To keep people protected this Fourth of July, researchers at the Virginia Tech-Wake Forest University Center for Injury Biomechanics put a pair of eyes to the test.
Researchers inserted four different pressure sensors in each of the cadaver eyes, which were restored to simulate a living pair of eyes. They then blasted 10 grams of gunpowder 18 different times, at 22 centimeters, 12 centimeters, and 7 centimeters away from the cornea of the eyes. The researchers also tested firecrackers at different distances from the eyes.
Corneal tears were the most common injury seen at each distance. The researchers found it was most likely from tiny shards of unspent explosive debris that sprayed onto the eye. The closer the blasts, the more serious the injury, according to the study.
"We can now prove it's the impact of the projectile and not the pressure waves that can cause eye injury," said Stefan Duma, the principal study investigator and department head of biomedical engineering at Virginia Tech University.
However, a corneal tear is not the only injury of concern, according to Dr. Sandra Block, medical director of school-based vision clinics at the Illinois College of Optometry and a board member of Prevent Blindness America. In many cases, corneal tears heal over time without long-lasting effects.
"Broken bones and lacerations in and around the eye are more concerning," Block said.
Since the study used eyes that were removed from the cadaver, the researchers could not study the the blast impact on the face and around the eyes.
Burns caused by sparklers or other fireworks held in close proximity are also common, said Block, who was not involved in the study. Childeren are at particular risk for these injuries since they are often given smaller fireworks including bottle rockets and firecrackers, which are highly dangerous, she said.
"Children should not be given sparklers or other novelties because they don't know enough to protect themselves," she said.
The preliminary research, funded by the Department of the Defense, aims to look at how larger explosions such as improvised explosive devices shape eye injuries in combat soldiers, Duma said.
"But our findings do have applications for consumer products," he said, adding that studying fireworks was a way for them to start small.
The findings helped researchers clarify that using goggles or an eye shield is beneficial in reducing the impact and potentially preventing eye injuries.
"If it was a blast wave that caused the injury, then a goggle might have no effect," Duma said.
Goggles may also be an important safety object for those who may be considering setting off fireworks at home this year, he said.
But according to Block, the only way to prevent eye injuries from fireworks is to leave the show to the professionals.
"There's no reason why any of that should take place," said Block. "They are all avoidable accidents."