What process captures light rays in the mechanism of vision?

• A. Reflection of light rays
• B. Transmission through the lens
• C. Absorption by the cornea
• D. Concentration of light on the retina

Answer: (D)

This question tests how light is focused in the eye to form an image on the retina. Light must be gathered and directed so that a sharp image lands on the photoreceptors, which then convert it into neural signals. The concentrating of light on the retina is achieved by the eye’s optical system—the cornea and lens—that bend and converge the rays to produce a focused image on the retina. If light were merely reflected, it wouldn’t reach the retina properly; if it only passed through the lens without being concentrated, the image would be blurred; and if the cornea absorbed light, little would reach the retina. So, concentrating light on the retina best describes how light is captured for vision.