|The eye is an amazing organ. It allows us to see a beautiful sunset or read our favorite book. We can see a faint star at night or a baseball game on a bright sunny day. Each part of the eye has a very important function. Let's learn about them. The white part of the eye is called the SCLERA. It is a very hard substance that gives our eye it's shape and provides a protective coat. It is covered by the
CONJUNCTIVA, a clear skin. When our eye gets red and mattery from
an infection, it is usually the blood vessels beneath the conjunctiva that give the "pink eye" appearance.
The process of vision begins with the CORNEA. Light rays are bent by this front, clear window of the eye so they pass through the PUPIL. The pupil is the black center opening in the IRIS or colored part of the eye. Two types of muscle fibers make up the iris. When the long muscles pull, the pupil opens wider. When the circular muscles pull, it gets smaller. By working together, just the right amount of light can enter our eye on a bright sunny day or at night.
A clear, watery liquid known as the AQUEOUS HUMOR fills the space between the cornea and the iris. New aqueous is constantly being made and the old must go out of the eye to keep the pressure within the eye balanced. Glaucoma is a disease where the eye has a pressure that is too high.
The LENS of the eye is a flexible, clear structure located just behind the iris. It is attached to ligaments and can flex to allow our eye to see distance objects and change focus to see near as well. As our eye ages, the lens hardens and loses it's ability to focus on near objects. This condition is called presbyopia and is corrected by wearing reading glasses, bifocals, or contact lenses. If the lens becomes cloudy, it is known as a cataract.
A gel called VITREOUS HUMOR fills the middle four fifths of the eye. It is transparent and has the consistency somewhat firmer than an egg-white. When we see "floaters" they usually are originating from material floating within the vitreous.
The innermost lining of the eye is known as the RETINA. It acts much like the film of a camera by catching light that enters the eye. RODS are cells in the retina that see in dim light. CONES detect bright light and color. The cones are concentrated in the central area of the retina known as the MACULA. If this area of the retina degenerates, we lose our ability to see small detail. The OPTIC NERVE bundles the retinal nerve fibers together and sends them to the brain. Did you know that we each have a unique pattern of retinal blood vessels? Just like our fingerprint, no one else has a retina exactly like ours. Special instruments used during an eye examination allow us to see your optic nerve as well as your retina and blood vessels. Can you find the optic nerve and the blood vessels in this retinal photograph?
Be sure to ask us for the latest information
at your next eye examination.