Josie walks into her house from outside, as she enters a dark room, a spider falls in front of her face, describe the changes that occur in the eye to visualise a close up object in the dark.

This question aims to address the following learning objective:To be able to relate the structures of the eye to their functions. This includes: accommodation to focus on near or distant objects and adaptation to dim light.In the dark, the decreased level of light on the eye is detected by the retina and this information is carried to the brain via the optic nerve. The signals from the brain cause the radial muscles of the iris to contract and the circular muscles of the iris to relax resulting in dilation of the pupil to let more light into the eye. To focus on a near object, the ciliary muscles of the eye contract and the suspensory ligaments loosen, this means that the tension of the lens decreases and the lens takes a thicker, more convex shape. When light passes through the convex lens light is refracted more strongly and the image is focused on the retina.