OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What is the main function of the lens in the eye?

1. To protect the eye from the environment

2. To regulate blood flow to the eye

3. To refract light and focus it on the retina

4. To control the color of the eye

The correct answer is: To refract light and focus it on the retina

The lens in the eye plays a crucial role in vision by refracting light and focusing it directly onto the retina. This process is essential because, without the lens's ability to bend light rays appropriately, images would not be clear, and visual acuity would be impaired. The lens adjusts its shape to help focus on objects at varying distances, a process known as accommodation. This adjustment is crucial for seeing both near and far objects clearly. The other options do not describe the primary purpose of the lens. Protecting the eye from the environment relates more to the cornea and eyelids, while regulating blood flow is a function of the eye's vascular system, not the lens. Controlling the color of the eye pertains to the iris, which is responsible for the eye's pigmentation and controlling the amount of light that enters but does not involve the lens's function.