A tiny pair for a riddle

Transparent twins in shape and size
They’re such a tiny pair
With a diameter about one fourth of an inch
One’s light blue, the other light brown
Daily they needed to be washed and moistened
At night they like to be soaked asleep
Deep in their beds of small bowls filled with liquid

What are they?

Answer will be coming up on Wednesday.

Hint: They make you see things more clearly!