pupil

(PYOO-pul) Speaker

The round opening in the center of the iris (the colored tissue that makes the "eye color" at the front of the eye). The pupil changes size to let light into the eye. It gets smaller in bright light and larger as the amount of light decreases.

Anatomy of the eye showing the outside and inside of the eye, including the eyelid, pupil, sclera, iris, cornea, lens, ciliary body, retina, choroid, optic nerve, and vitreous humor

Figure

Anatomy of the eye showing the outside and inside of the eye, including the eyelid, pupil, sclera, iris, cornea, lens, ciliary body, retina, choroid, optic nerve, and vitreous humor.