To transmit visual information from the retina to the brain.
Explanation
The human eye functions as a natural optical instrument, analogous to a camera, where specific components are responsible for light regulation, focusing, image formation, and signal transmission.
- To regulate the intensity of light entering the eye. is incorrect: The regulation of the amount of light entering the eye is the function of the iris. It adjusts the size of the pupil (the aperture) to control light intensity, similar to the diaphragm of a camera.
- To focus the image onto the retinal screen. is incorrect: The focusing of light rays onto the retina is primarily performed by the cornea and the crystalline lens. The lens changes its shape (accommodation) with the help of ciliary muscles to focus on objects at different distances.
- To transmit visual information from the retina to the brain. is correct: The optic nerve connects the eye to the brain. After the retina converts the focused light image into electrical impulses via photoreceptor cells (rods and cones), the optic nerve transmits these electrical signals to the visual cortex of the brain for interpretation.
- To protect the eye from external particulate matter. is incorrect: Protection against external particulate matter is provided by the eyelids and eyelashes, not the optic nerve.
Key Takeaway: In the human visual system, the lens focuses light, the retina detects it, and the optic nerve transmits the resulting neural signals to the brain for visual perception.