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

How does the eye focus an image?

1. Using the retina only

2. By closing the eyelid

3. Light being bent by the cornea and lens

4. By signaling to the brain without bending light

The correct answer is: Light being bent by the cornea and lens

The process by which the eye focuses an image primarily involves the bending of light, a phenomenon known as refraction. The cornea, which is the transparent front part of the eye, plays a critical role in this process as it bends light rays entering the eye. After passing through the cornea, the light then travels through the aqueous humor before reaching the lens. The lens further adjusts the focus of the light rays by changing shape; this ability to change shape is known as accommodation. Together, the cornea and lens ensure that the light rays converge precisely onto the retina, where the image is then projected. This intricate mechanism allows for clear and focused images at various distances, highlighting the importance of both the cornea and lens in focusing images properly on the retina. The retina then detects the focused light and converts it into electrical signals, transmitting them to the brain for visual processing. Therefore, the correct answer accurately reflects the key components of the eye's focusing system and the role of light refraction in forming clear images.