The warning comes after three people were presented to hospital on separate occasions with serious eye injury after being shot at by a Nerf gun.
All three were in pain and had blurred vision. And they all had internal bleeding in the eye (hyphema).
One of the three patients was a child, who had also developed swelling of the outer layer of the eye (cornea), and the inner layer of the eye (retina), from the force and speed of the bullet fired by the gun.
The patients were given eye drops, and when they went for their check-ups their sight had returned completely and the bleeding had stopped.
These types of injuries can have a serious impact, say the authors. A projectile travelling at high speed can cause irreversible vision loss*. Children should protect their eyes when playing with these guns, they advise.
"Sports in which the risk of [eye] trauma is relatively high, such as squash ball, have seen an introduction of protective eyewear in the UK," write the authors.
"This case series emphasises the seriousness of [eye injury] from Nerf gun projectiles and calls into consideration the need for protective eyewear with their use," they add.
One of the injured patients commented that the bullets, also known as darts, were generic versions and were harder than the branded versions. Parents may not be aware of this, say the authors.
The safe age limit for Nerf gun use in children may need to be reviewed, they suggest.