Fill in the Blanks IGCSE Bio: Pupil reflex and accommodationOnline version Fill in the blanks by Tharwat A 1 antagonistically circular pupil relaxation high light radial circular constricts relaxing radial control circular Pupil reflex : The of the eye can expand and contract to the amount of that enters the eye . This action is carried out by two sets of muscles , muscles and muscles , which work . At low light intensities , the pupil dilates to allow more light to enter the eye by the muscles and contracting the radial muscles . At light intensities , the pupil to limit the amount of light entering the eye by of the muscles and contraction of the muscles . This is to prevent the eye being damaged by the bright light . 2 suspensory refracted altered retina fatter ligaments relax thinner contract Accommodation : The eye can focus on both near and far objects . This is achieved by changing the shape of the lens , which is controlled by ciliary muscles and suspensory ligaments . These work antagonistically . The shape of the lens , as well as its curvature , is to change the way light is onto the , focusing the image . To focus on near objects , the ciliary muscles whilst the , making the lens and curved . To focus on distant objects , the ciliary muscles relax whilst the suspensory ligaments contract , making the lens and less curved .