Iris – coloured part of eye that adjusts pupil size
The iris– the flat, ring-shaped, muscular, coloured part of the eye which surrounds the pupil – is the eye’s light regulator. The iris adjusts the size of the pupil to increase or reduce the amount of light that enters the eye.
Many different coloured irises surrounded the pupils.
The iris consists of two layers: the front pigmented fibrovascular known as a stroma, the stroma connects to a sphincter muscle (sphincter pupillae) and, beneath the stroma, pigmented epithelial cells.