The way human eyes work to allow us to see things around us is that first light bounces off of an object, which then enters the eye through your cornea, which then bends the light.
Once the light bounces off an object, enters your eye through your cornea and bends the light, the light then passes through your pupil, where the iris then controls the amount of light.
Then, the lens of the eye focuses the light onto the retina, which then turns the light into signals that are then sent through your Optic Nerve and then finally to your brain.
The cornea of the eye acts as a clear window, which helps to bend the incoming light.
Your colored iris changes the size of your dark pupil hole.
And then it gets smaller in bright light and larger in dim light to control the amount of light that enters.
The lens sits behind your pupil and then fine tunes the focus of light and it changes it's shape to help you see things up close or far away.
The way your body turns light into sight involves the retina, rods and cones, electrical signals and the optic nerve and brain.
The retina is a thin layer at the back of the eye, which catches the focused light.
Rods and cones are special cells in your retina and the rods help you see in the dark and spot shapes.
The cones help you see colors and fine details in bright light.
And these special cells in the retina which are the rods and cones change the light into tiny electrical messages.
And then finally the optic nerve carries these messages to your brain.
Then your brain turns the upside down view right side up and adds color and depth so that you know what it is that you're looking at.
All this happens very fast without you even needing to do anything or thinking about it.