the pupil is actuly a hole into your head and doctors can tell if your healthy by looking through them.
the following protect your eye:
eye lids:close eyes from light. eye lashes: they move water fromoutside away from eye. eye brows: they stop swet or other stuff. tears: they drain stuff thats in the eye out like smells.
the shclera blocks light from your eye. the iris can make the pupil smaller or bigger.