1- light is focused primary by the cornea the clear front surface of the
eye act like camera lens..
2-the iris controlling the amount of light reaching the back of the eye by automatic adjusting the size of pupil
3- lens is direct behind the pupil and further focuse light through process called accommodating this lens help the eye automatically focuse and approach the object
4- light focuse by the cornea and crystalline lens and limited by iris and pupil then reach the retina..
The light sensitive inner lining of back of eye . the retina act like electronic image sensor of digital camera converting optical image into electric signals
The optic nerve transmit these signals to visual cortex the part of brain that control our sense of sight