Anatomy Practice Exam

Which part of the eye is responsible for focusing light onto the retina?

1. The cornea

2. The aqueous humor

3. The lens

4. The vitreous humor

The correct answer is: The lens

The lens is the part of the eye responsible for focusing light onto the retina. Located behind the iris and pupil, the lens is a transparent structure that can change shape to adjust the focal distance, allowing us to see objects at varying distances clearly. This process is known as accommodation. When looking at nearby objects, the lens becomes more curved to bend the light rays more sharply so that they converge precisely on the retina. Conversely, when focusing on distant objects, the lens flattens out to allow for a broader focus. The cornea also plays a significant role in refracting light as it enters the eye but does not adjust its shape to focus images at different distances as the lens does. The aqueous humor contributes to maintaining intraocular pressure and providing nutrients to the eye tissues but does not have a role in focusing light. The vitreous humor, a gel-like substance filling the main cavity of the eye, helps maintain its shape and provides some structural support but does not contribute to the focusing of light on the retina. Thus, the lens is the correct answer regarding focusing light accurately onto the retina.