
My second-most unsettling experience thinking about insects in my eyes was a real-life incident, when I accidentally jogged straight into a swarm of gnats on a trail. I couldn’t shake the sensation that something was still lodged in my eye, and hours later, I finally managed to remove a dead(?) gnat from the depths of my eyelid using a Q-tip. Nothing could top that—except reading about face flies on Gizmodo this morning.
Not long ago, a woman in California ran right into a cloud of flies on a trail, only to discover later that one of them had deposited worms into her eye. 'She remembers swatting the flies from her face and spitting them out of her mouth,' the report states. Over the next month, she and two ophthalmologists located a total of four worms in her eyes.
I want to clarify one point: face flies and eye worms are two separate entities, though they work together to create this particular brand of body horror. Face flies drink the tears of animals, while eye worms reside inside the face flies’ bodies, in their mouthparts, and make their way into the eye when the fly feeds. Occasionally, if a face fly happens to land on a human eye, someone like you or me—like the woman on the California trail—could find themselves with a collection of tiny worms inside their eye.
The positive side: this is incredibly rare
There are various types of eye worms, and part of the reason this recent case is making headlines is because this and another case from last year were caused by a different species (Thelazia gulosa) than the one typically found in human eyes (Thelazia californiensis).
These worms primarily affect animals; when they end up in a human eye, it's usually by accident. The worms cannot reproduce in your eye, so even if you do become infected, they won’t stay there forever.
The key takeaway for both you and me is quite straightforward: seek medical help if your eyes are irritated and you’re unsure of the cause, or if you happen to find, well, worms in your eye. You can see an image of a Thelazia worm on this CDC page. They're tiny, like if you took a noodle and shrank it to the point where it was nearly, but not entirely, invisible.
For the medical professionals, the authors of the recent case study suggest that any eye worms be sent to a parasitology lab for identification—not just as 'yep, that’s an eye worm' but down to the specific species. This is because scientists are curious if the two cases in as many years suggest that T. gulosa is becoming more widespread, and if that’s the case, we should definitely keep a close watch (pun intended).
