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.
Iris and Pupil. The colored part of the eye is the iris. It is a muscle that controls the pupil, the opening in the middle of the eye that controls the amount of light coming in. Lens and Retina. The lens is behind the pupil and focuses light onto the retina, the light-sensitive cells on the back of the eyeball.