Some people say that eyelids are translucent, they're actually very opaque, when all people close their eyes when they're awake or sleeping in the light or in the dark, they see darkness because their eyelids block out light and eyelids create the absence of light, sometimes when they close their eyes when facing in the sun or light they see red in which is called ''red reflex''. Some people think that eyelids are translucent, they are wrong, eyelids are very opaque, why are eyelids are opaque?