Eyes work from the moment they open in the morning until they close at night, absorbing and processing tens of thousands of bits of information, such as colors, shapes and movements. However, the eye has some very basic functions, without which individuals would be significantly challenged in their daily activities.
Light Perception
The eye is designed to be photosensitive, meaning that it can detect different light intensities. Once light is admitted into the eye, it is focused on refracting surfaces, giving greater depth, focus and acuity to sight. Human eyes detect a very narrow range of wavelength electromagnetic radiation---between 380 and 760 nanometers, according to the Washington University Neuroscience Department. This wavelength is called the visible spectrum, and it falls between ultraviolet and infrared rays.
Focus Light
The pupil area regulates the amount of light that enters into the eye. This is done by adjusting the size of the pupil, working much like the shutter of the camera, according to the University of Michigan Kellogg Eye Center. Both the iris and pupil work together to control how much light is allowed into the back of the eye. The amount of light that enters the eye will increase the probability that an individual will be able to visualize images and record them in the brain.
Refraction
Once the light has been admitted into the eye, the cornea and the lens bend the rays and focus the image on the retina. However, the retina does not transmit the image correctly. The image comes in upside down, and according to the Washington Neuroscience Department, the brain accepts the image and inverts it so that the individual will see everything right side up.
Light Accommodation
The eye uses special cells called rods and cones to process the light. According to KidsHealth.org, there are approximately 120 million rods and 7 million cones in each eye. Rods cannot tell the difference in colors but allow the eye to see when it's very dark. Cones sense color but need more light than the rods to work well. There are three different types of cones, each sensitive to one of three colors: red, green or blue. When the eye processes these colors in the different cones, an individual is able to see millions of different colors.
Transmission of Information
The optic nerve, also part of the function of the eye, carries messages from the eye to the brain. The brain is then able to translate the information provided by the eye into an image. According to the Washington University Neuroscience Department, the brain receives information from both the eyes at the same time. Information crosses at the nerve level and travels to three different areas of the brain. Information that goes to the midbrain area is not a conscious idea, but rather produces pupillary reflexes and eye movements. Information sent to the thalamus is processed and carried to the visual cortex in the occipital lobe where the brain interprets the information into pictures.
Tears
The eye is created from delicate tissue that must remain moist in order to remain healthy. Tears lubricate the surface of the eye to keep it from drying out and protect it from dust and smoke. Every time the eyelids blink, a tiny amount of fluid helps to wash away germs or other particles.
