Cognitive behavioral therapy (CBT) is a type of psychotherapeutic treatment that helps patients understand the thoughts and feelings that influence behaviors. CBT is commonly used to treat a wide range of disorders, including phobias, addictions, depression, and anxiety.
The iris regulates the amount of light that enters your eye by adjusting the size of the pupil opening. In bright light, the iris closes (or constricts) and makes the pupil opening smaller to restrict the amount of light that enters your eye. The iris in bright light. In dim light, the iris opens (or dilates) and makes the pupil opening larger to increase the amount of light that enters your eye: The iris in dim light. In addition, it is the iris that determines your eye color.
For other uses, see Iris (disambiguation) . The iris (plural: irides or irises) is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupil and thus the amount of light reaching the retina.he iris develops from the anterior two layers of an embryonic neuroectoderm structure called the optic cup. The optic cup also produces the iris sphincter and dilator muscles.