system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Eye boogers, what are they? Why do they happen? What is their purpose?

A lifelong question of mine.
gpt
It's just dust and oil that your eye naturally builds up. It gets cleaned off and blows away when you're awake because you're blinking, but when you sleep, it all collects in your tear ducts and hardens into eye boogers. Since your eyes have to stay clean, they have a built-in self-cleaning system, and eye boogers are just the built-up result.