Which eye component is primarily responsible for converting light into neural signals?

• A. Cornea
• B. Iris
• C. Sclera
• D. Retina

Answer: (D)

Converting light into neural signals happens in the retina, the light-sensing layer at the back of the eye. Here, photoreceptor cells—rods for motion and low light, cones for color and detail—absorb photons and trigger phototransduction, a chemical change that generates electrical impulses. Those signals then pass through other retinal neurons to the ganglion cells, whose axons form the optic nerve carrying information to the brain for interpretation. The cornea and lens focus light but don’t convert it to signals; the iris adjusts the amount of light entering the eye by changing pupil size; the sclera provides structure. So the retina is where light is transformed into neural signals.