Even if the object does not shine by itself, why can we see it?
The eye is the organ that feels light. Even if the object does not shine by itself, why can we see it?
Most objects can reflect light without emitting light themselves. Light reflected from rough surfaces such as paper or wood is scattered in many directions. The eyes recognize this diffuse light. Therefore, people can see objects with a bit of light.
Focusing
The eye has to gather the light from one point on the object to the retina’s one point to see the objects in detail. If the lights are scattered all over the retina, we will lose focus.
To gather the emitted light into one point of the retina, a device acts as a convex lens. This is the cornea and lens of the eye.