Problem 8: Visual Comfort in Bright Light
Explanation
In bright light, the pupil of the eye contracts (becomes smaller). A smaller aperture blocks the “marginal rays” (light rays entering near the edges of the lens).
Marginal rays refract more strongly than central (paraxial) rays, leading to a defect known as Spherical Aberration, where light fails to focus at a single point. By constricting the pupil, the eye effectively stops down the lens system, allowing only the central rays to pass. This significantly reduces spherical aberration, resulting in a sharper image and reducing the strain on the eye to focus.
Answer: (b) Contraction of pupil in bright light reduces spherical aberration.