"Eye infections, in contrast ... caused by the larval stages of pentastomid parasites. Most human infections occur in the tropics and subtropics," says the journal paper. Tongue worms grow ...

So, it is likely that this is when its eyes are important," says Garm. Part of the explanation may be due to the fact that these worms see different wavelengths of light than we humans do.

This particular eye worm species has never been documented in humans, making Beckley’s case particularly unique, and a bit frightening. However, identifying the worms was only half the battle.