Why do we see darkness when eyes are closed?
Show answer & explanation
Answer: Eyelids block light from retina
Eyelids block light from retina ✓ — Correct! Eyelids are opaque tissue that blocks most external light from reaching the retina. Without light stimulating photoreceptors, no signals are sent to the brain. You perceive this absence of visual input as darkness. Some light can penetrate eyelids (try closing eyes facing bright light), but mostly, eyelids provide effective light barriers for sleep and protection!
Brain shuts off vision — Wrong. Brain continues processing vision. Darkness is the absence of light signals because eyelids block light from reaching the retina.
Optic nerve stops working — Wrong. Optic nerve works fine. Eyes see darkness because eyelids block light from stimulating photoreceptors in the retina.
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