What Is the Process of Focusing the Eye Called?

While driving, you spot a faraway road sign and then glance at your dashboard just inches away. To see both clearly, your eyes must accommodate for differences in distance.

Definition

• The process of focusing the eye is called accommodation, states "Taber's Cyclopedic Medical Dictionary, 19th Edition" In accommodation, the eye's lens bends incoming light rays so that they converge on the back interior of the eye (retina), notes the book "Biology, 5th Edition," by Neil Campbell et al.

Lens

• For distant objects, the lens is flat. For nearby objects, the lens becomes more spherical, according to "Biology."

Eye Muscle

• The shape of the lens is controlled by the ciliary muscle. As this muscle relaxes, fibers connecting it to the lens tighten, making the lens less spherical, observe Arthur Vander et al in their book "Human Physiology, 8th Edition."

Near Vision

• For close-up objects, the ciliary muscle contracts. Simultaneously, the elasticity of the lens enables it to assume a more spherical shape, according to "Human Physiology."

Aging

• With age, the lens suffers a decrease in elasticity, a condition called presbyopia. This makes it harder to focus on close-up objects, state Sue Huether and Kathryn McCance in their book "Understanding Pathophysiology, 2nd Edition."