When you were younger, I’m sure you were explained how people see and interpret things. Typical examples of explaining sight include referring to cameras and how they operate. Demonstrating how your eyes see and how cameras work is an effective way to help people understand vision but our vision is much more complicated than that.
Our eyes are light receptors. Light is reflected off of an object which is then transferred into our eyes and processed by our brains. There are many different parts of the eye that allow the process of sight to happen. The components of a human eye are complex and deserve some explanation to understand how we see.
The areas of the eye that we use to perceive light consist of the pupil, cornea, retina, lens, and optic nerve. All of these areas work together at incredible speeds to process information from our eyes. In the retina of the eye, millions of light receptors differentiate colors and textures of objects we see. These receptors are divided into two categories, cones, and rods. The cone receptors in the retina are responsible for determining the color of the object we are perceiving. The rods in the retina give us the contrast between light and dark. The other components of the eye that were mentioned all help the receptors in the retina perceive and take in the light.
Cornea & Pupil
The cornea is the outermost layer of the eye. The best way to describe the cornea is to think of it as the window to the eye. The cornea allows light to safely pass through where the pupil filters how much of the light gets through. The pupil is the dark circle in the center of your eye. The pupil can frequently change in size depending on how much light is available to you. In the darkness, the pupil expands to allow as much light as possible into the eye. On a sunny day, the pupil shrinks to allow only a necessary amount of light through. The pupil can also alter its size based off of a person’s emotional state. Someone experiencing excitement can have a larger pupil size.
Lens & Optic Nerve
Your eye’s lens helps you to focus on objects both near and far. Very similar to a camera lens, your lens will adjust to the distance of the object you are trying to perceive. Through aging, the process of your lens adjusting becomes more difficult and may cause problems later on in life. Your optic nerve is the last component of your eye that is needed to perceive sight. The optic nerve runs from the back of your retina to the brain where the information received by your eye is interpreted and perceived.