Lens

Definition

The lens is a transparent, flexible structure in the eye that focuses light onto the retina. It changes shape to adjust for near and far vision through a process called accommodation.

5 Must Know Facts For Your Next Test

1. The lens is situated directly behind the iris and pupil.
2. Ciliary muscles control the shape of the lens for focusing light.
3. Cataracts are a common condition where the lens becomes cloudy, impairing vision.
4. The lens lacks blood vessels and receives nutrients from the aqueous humor.
5. Presbyopia is an age-related condition where the lens loses its flexibility, making it difficult to focus on close objects.

Review Questions

• What role does the lens play in focusing light within the eye?
• How do ciliary muscles influence the shape of the lens?
• What are cataracts, and how do they affect vision?

Related terms

Retina:

The light-sensitive layer at the back of the eye that converts light into neural signals.

Ciliary Muscles: Muscles attached to the lens that change its shape for focusing.

Iris:

The colored part of the eye that controls how much light enters through the pupil.