"There were two parents who were physicians at the practice," Carter's mom, Christine Nattrass, said of the May 2010 incident. "They said: 'you're just going to get a real good shiner buddy.'"
A day or two later, something wasn't right. Carter, now 11, told a teacher he saw a black string of cobwebs in his line of vision. The Nattrass family realized they were dealing with something more serious.
Carter suffered from a retinal detachment, a condition that Dr. Peter Kertes says is considerably more complicated in young children.
"The retina lines the back of the eye and when it is separated, we put a variety of substitutes in the eye, things that fill that volume and they help to push it back into place," said Kertes, Carter's doctor and the head of the Department of Ophthalmology at Toronto's Sunnybrook hospital.
When the retina is not in place, it leads to blurred or lost vision.
While Carter's case is an extreme one, Kertes said eye injuries are more common in the summer months, when kids are more likely to be outside playing sports — often without protective equipment.
Kertes notes that such gear has helped protect athletes in hockey, but is not yet part of the attitude of warm-weather activities including soccer, baseball and basketball.
"For kids and adults when they play hockey, they need to wear face masks, which has reduced the amount of eye injuries dramatically," he said. "But it's not the same for summer sports."
Wearing eye gear can be particularly crucial for children, noted Dr. Surjinder Sahota, president of the British Columbia Association of Optometrists, because their depth perceptions are still developing.
"It's easy to misjudge where the ball or object is," she said, adding that 90 per cent of sports-related eye injuries can be prevented with proper eyewear.
Dr. Keith Gordon, vice-president of the Canadian National Institute for the Blind, thinks there should be rules or guidelines forcing players to wear protective eye gear.
"I looked at the rules of baseball and all it says is all players shall wear helmets to cover their head," he said.
Still, change will likely be slow to come. André Lachance, manager of baseball operations at Baseball Canada, said in an email that the organization has studied the main risks of the sport, and that eye injuries isn't one of them.
Summer sports are not the only eye hazard facing kids. Being in the sun for an extended period of time can cause long-term damage to the eyes.
"Spending time in UV sun exposure during your childhood can lead to an increase in eye disease," said Sahota, citing degeneration of the cornea, tissue growth on the surface of the eye and cataracts.
She recommends children wear sunglasses and caps, and avoid exposure when the sun's rays are strongest.
Trips to the beach or playground can also result in sand in the eye, which can cause a corneal abrasion.
"Although it may seem small, it can cause great discomfort - pain, watery eyes, blurred vision," she said, adding that the best treatment is to rinse the eye out with water.
On the playing field, Kertes recommends sports glasses with lenses made out of polycarbonate rather than regular plastic.
"Polycarbonate is the material that has best protection of the eye," he said. "It's a shock-proof material. It's strong, robust and protects the eyes very well."
And he notes that the eyewear, which can be purchased at most optical shops and sports stores, are not as awful looking as kids perceive them to be.
"They have these visions of these very funny-looking glasses that they have to wear," he said. They're cool-looking, protective glasses."
Carter, for one, is a convert. He may have to undergo further surgery and will never see as clearly as he once did.
"I wear (protective glasses) whenever I play sports," he said in an email. "I also wear them during gym and sometimes at recess if we are playing soccer."
Nattrass wishes there was more awareness about the importance of safety glasses. She says even those who saw what happened to Carter haven't changed their habits.
"It's shocking because some of his really close friends, even the coach (that threw the pop fly ball), his son still doesn't wear safety glasses ... This is a preventable injury."
Carter, meanwhile, hasn't been dissuaded from returning to the playing field.
"I have played hockey for many years and am really excited to start playing again," he said, adding he was going to hockey camp this summer but can't due to his most recent surgery.
Added Nattrass: "I don't know how he plays anything but he does," "He's the bravest kid I know."
ALSO: Tips to avoid eye injuries: