Optics is the branch of physics that deals with light and vision. It is primarily the generation, propagation and detection of electromagnetic radiation having wavelengths greater than x-rays and shorter than microwaves. Most optical phenomena can be accounted for using the classical electromagnetic description of light. However, often times these descriptions are too difficult to apply in practice. Practical optics is usually done using simplified models.
Visual perception is the ability to interpret information and surroundings from visible light reaching the eye. The perception which results is known as eyesight or vision. The physiological components involved in vision are referred to as the visual system. There are many focuses of research on visual systems in the fields of psychology, cognitive science, neuroscience and molecular biology.
The visual system in humans allows people to assimilate information from the environment. The act on seeing starts when the lens of the eye focuses an image of its surroundings onto a light-sensitive membrane in the back of the eye. This is called the retina. The retina converts patterns of light into neuronal signals. These signals are processed by different parts of the brain in a hierarchical fashion from the retina to the lateral geniculate nucleus, to the primary and secondary visual cortex of the brain. Signals can also travel directly from the retina to the Superior colliculus.