Which structure focuses light onto the retina?

Which structure focuses light onto the retina?

• A. Iris
• B. Cornea
• C. Lens
• D. Optic nerve

Answer: (C)

The lens is the structure that focuses light onto the retina. Light entering the eye is bent primarily by the cornea, but the lens provides the fine-tuning needed to form a sharp image on the retinal surface. It does this by changing its shape through the action of the ciliary muscles, a process called accommodation, which lets you focus on objects at varying distances. The iris controls how much light enters by adjusting pupil size, and the optic nerve carries the visual signal to the brain, not focusing the light.

The lens is the structure that focuses light onto the retina. Light entering the eye is bent primarily by the cornea, but the lens provides the fine-tuning needed to form a sharp image on the retinal surface. It does this by changing its shape through the action of the ciliary muscles, a process called accommodation, which lets you focus on objects at varying distances. The iris controls how much light enters by adjusting pupil size, and the optic nerve carries the visual signal to the brain, not focusing the light.