The eye responds to bright light to protect the retina from damageThe bright light triggers a reflex that makes the pupils smaller, meaning less light enters the eyeAs with all reflexes, there is a stimulus, receptor and effectorThe stimulus is the light, the receptor is the light receptors in the eye and the effectors are the radial or circular muscles.In the response to bright light, the circular muscles contract, making the pupils smaller. In the response to dim lighting, the radial muscles contract, making the pupil bigger.