Cornea Associates of Texas would like to help you better understand how your eyes work. Through your eyes, you see and interpret colors, dimensions, and the very shapes of the world. Your eyes are able to see in a variety of lighting and do this by converting light rays into electrical signals and sending those signals to the brain. The brain interprets these signals as visual images.
Although the eyes are crucial to everything you want to do, whether reading, participating in sports, driving a car, watching a sunset, playing on a beach, or writing a letter, they are often taken for granted. Let’s take a minute to discuss the parts of the eye and how they work together to achieve sight.
There are ten distinct parts of the human eye. They include: the cornea, conjunctiva, sclera, iris, pupil, lens, optic nerve, sclera, vitreous, retina, and optic nerve.
Here are the definitions of these parts:
The cornea provides focus when light images enter your eye, much like the lens of a camera. There are layers of tissue that make up the cornea. The outer surface is the epithelium. which is the eye's protective layer. The epithelium is made up of highly regenerative cells, which have the ability to grow back within three days.
The conjunctiva lines the outer sclera and provides a protective barrier for the eye. Tiny secretory glands in the conjunctiva produce the tear film to lubricate the surface of the eye.
The sclera represents the part that is known as the “white” of the eye. The sclera's purpose is to provide structure, strength, and protection to the eye.
The iris is the colored part of the eye. (i.e. blue, green, brown, and hazel). The primary function of the iris is to control the size of the pupil. This is achieved through contraction and expansion of the muscles of the iris.
The pupil is the 'black circle' seen in the eye. The function of the pupil is to control the amount of light entering the eye. If the environment is dark, the pupil expands to allow more light to enter and reach the back of the eye. In bright light, it becomes smaller to allow less light to enter the eye similar to the aperture of a camera.
The lens is a clear structure located behind the pupil. It focuses the images we see as well, like the lens of a camera. This is accomplished by altering its shape. Around age 45, many lenses become less flexible. This is a normal transition with age, which results in a condition is called presbyopia. As we age, almost all of us will develop a varying degree of clouding and hardening due to cataract formation.
This is a clear, gel-like substance located inside the eye. It fills the interior of the eye.
The retina is the delicate membrane of light-sensitive nerve tissue. It lines the inside wall of the eye and acts much like the film in a camera, capturing an image and converting it into electrical impulses, which are transmitted to the brain via the optic nerve.
The optic nerve carries image signals from the retina to the brain.