[ELI5] Why are our eyes sometimes blurry within the hour or so after we have woken up from a night’s sleep? Why is it sometimes one eye more than the other?
In: Biology
Among other reasons, you might have junk on the surface of your eye, such as dust or loose eyelashes. There are [three sets of glands](https://www.merckmanuals.com/home/eye-disorders/biology-of-the-eyes/protective-features-of-the-eyes)—one for tears (water), one for mucus, and one for lipids. The three secretions mix together in a protective coating your eye.
You might wake up with an eyelash or other small bits stuck in there, surrounded by a small glob of mucus that keeps it from shredding your eye as you blink. You might also wake up with the coating having partially dried out, making things blurry for a moment.
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