Iris's place in the eye is the uvea, which is the middle layer of the eye. It is composed of the choroid, ciliary body, and iris. The choroid is a layer of blood vessels that supplies oxygen and nourishment to the eye. The ciliary body is responsible for controlling the shape of the lens and the amount of light entering the eye. The iris is the colored part of the eye that controls the size of the pupil and the amount of light entering the eye.