Red-Eye occurs when light reflects from which structure in the eye?

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

Answer: (C)

Red-eye appears because the reflection comes from the retina, the light-sensitive layer at the back of the eye. When a bright light, such as a camera flash, illuminates the eye, light passes through the pupil, hits the retina, and reflects back out through the pupil. The retina is rich in blood vessels, which gives the reflected light a reddish color, producing the red-eye effect in photographs. The other structures don’t produce this red glow: the cornea on the front surface tends to create small white highlights, the iris reflects its own color, and the lens would produce different reflections that aren’t red.