Question

what are the functions of cornea, iris, ciliary muscle and crystalline lens?​

Answer 1

Answer:

The function of: Cornea: When light enters the eye, most of the refraction occurs at the surface of cornea. Iris: It is a dark, muscular diaphragm that controls the size of the pupil. Crystalline lens: Helps in the finer adjustment of the focal length required to focus objects at different distances on the retina.

Answer 2

The cornea acts as the eye's outermost lens. It functions like a window that controls and focuses the entry of light into the eye. The cornea contributes between 65- 75 percent of the eye's total focusing power. When light strikes the cornea, it bends--or refracts--the incoming light onto the lens. In humans and most mammals and birds, the iris (plural: irides or irises) is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupil and thus the amount of light reaching the retina. Eye color is defined by that of the iris. A circular muscle that relaxes or tightens the zonules to enable the lens to change shape for focusing. The zonules are fibers that hold the lens suspended in position and enable it to change shape during accommodation The crystalline lens, or lens, is a bi-convex structure in the eye that is transparent and which works with the cornea to refract light to focus on the retina. It's very similar in its working to a man-made spectacle lens.