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.
Not necessarily. If you are in very bright lighting, your pupils will constrict to limit the amount of light allowed to enter your eye. This protects the retina from damage. Likewise, in very low light levels, your pupils will dilate (enlarge) in order to allow more light into the eye and improve vision. This is a normal process.