I've got a lard worm in my eye!

From PSmicrographs.

Actually, almost EVERYONE has lard worms in their eyes. That's the common name for the eyelash mites also known as Demodex folliculorum.

The lard worms are only a hundredth-of-an-inch long, so you can't see them. And not seeing them is good because lard worms are gross! (In that photo, the lard worms are climbing out of a hair follicle.)

This website that takes a more alarmist view of the lard worm. I love the banner graphic:

"Not my SEBACEOUS gland!"