The "black center" of the eye, responsible for controlling the amount of light entering the eye.  Add'l keywords/misspellings: pupill eyecenter dark part

The EyeCyclopedia™ is a collection of eye care terminology created by
practicing optometrists and ophthalmologists. The information provided is not intended
to be a substitute for regular medical care or to diagnose or treat
any medical condition, and should be used only as a supplemental source of information.
Please consult your doctor if you have any questions or concerns about your eye health.