Question

Give scientific terms for adjustment of the eye in order to obtain a clear vision of objects at different distances.

Answer 1

Eye is a convex lens. Light rays that enter it parallel to its axis, cross each other at one point. The image forms on the retina at the eyes back side. The shape of the lens is controlled by the tiny muscles that are present. Cells in the retina will absorb light and convert it to electrochemical impulses which then go to the brain by optic nerve.

Complete answer:
- The eye has several components like cornea, pupil, lens, iris, sclera and retina. They have a coordinated system to capture images and send them to the occipital lobe of the brain through the optic nerve.
- The lens of the eye is of converging type and thus the light rays are bent. It has a transparent structure which is held intact by the suspensory ligaments which are attached to the ciliary body.
- Accommodation is a phenomena by which the eyes of vertebrates change the optical power to focus on any object at different varying distances. Hence, the ability of an eye to adjust the focal length is what we refer to as accommodation.

Therefore the answer is ‘Accommodation’.

Note: There are photoreceptors present inside the eyes. They are of two types; rods and cones. Rods are mainly responsible for the black and white images and the cones make the color vision possible. For the flexible movement of eyes, there are the superior and inferior rectus muscles. They ease the upward and downward movement of eyes and are controlled by the oculomotor nerve. The tears that are released from the eyes are by the lacrimal glands and they provide a good lubrication for the eyes.