Some people think Nerf darts are safe because they’re ‘soft.’ But three patients at the heart of a medical report all had days or weeks of pain and blurred vision from toy dart injuries.

The report, published in BMJ Case Reports, reinforces what that the American Academy of Ophthalmology has said many times. Projectile toys are not safe. The three cases, treated at Moorfield’s Eye Hospital in the United Kingdom, underscore the serious nature of eye injuries during playtime.

No one chooses gifts with the intent to harm, but some popular children’s toys can cause serious injuries. According to the U.S. Consumer Product Safety Commission, nearly 252,000 toy-related injuries were treated in emergency rooms in 2014, and and almost half of these injuries affect the head or face...