It's the transparent part of the eye which bends those rays of light and focuses the image on the back surface of the eyeball. The lens will become thicker. Muscles will squeeze the lens, making it thinner so that you can see the image clearly. Once the light travels through the lens, it must still travel through lots of clear jelly, called the vitreous humor, which makes up most of the eye. But, finally, the light makes it to the back surface, or retina, of the eye.
Rods register shapes and respond to low levels of light.
Then, through optic nerves, these light-sensitive cells send information to the brain. It's the brain's job, not the eye's, to translate those upside-down images and interpret the information it receives into visual meaning that you can understand. Sometimes the lenses in peoples' eyes don't properly focus light on the back of the retina. If an eyeball is too short, the image will fall behind the retina. People are then called far-sighted, because their eyes can focus on things far away but not close up.