About the Eyes

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About the Eyes

Patient Info

About UsFor many of us, eyes are the first thing we notice when we meet someone new. We think of them as the windows of the soul, and spend plenty of time staring into the eyes of people we love. But, do you know how eyes work? Do you know about the common vision problems that can affect you and your loved ones?

Our eyes are hard at work all the time. They give us valuable information about the world around us, creating images like a highly advanced camera.

At Whitten Laser Eye, your eyes are in the best of hands. The information on these pages will help you understand your eyes and common vision problems. Then call us to schedule your vision evaluations of FREE LASIK Consultation. You will discover all the ways you can see the world more clearly.

Understanding Your Prescription

Common vision impairments such as nearsightedness, farsightedness, and astigmatism are measured in units referred to as diopters. A diopter will be a whole number. This number represents the amount of adjustment needed to correct your vision. The numbers will increase with the intensity of your nearsightedness, farsightedness, or astigmatism.

A typical prescription will look something like this:
-3.00 -1.50 X 180

The first number, -3.00 in this example, identifies the degree of your nearsightedness or farsighted. Nearsightedness is indicated by a negative sign, while farsightedness is indicated by a positive sign.

The second number you encounter, here -1.50, identifies your degree of astigmatism. This number may be written with a negative or positive sign.

The third number, 180 in the example, identifies where your astigmatism is located. 180 identifies the axis, letting you know that your astigmatism is horizontal. If the number were 90, the astigmatism would be in the vertical axis.

This prescription indicates that the patient is mildly nearsighted, with a moderate degree of astigmatism in a horizontal direction.

The Whitten Laser Eye staff will determine and help you understand your unique prescription, as well as the best options for improving your vision.

How Your Eyes Work

The human eye is made of many different and intricate parts, all working together to provide you with sight. Your eye is much like a camera in the way that the pieces work together to view the world around you. The eye is a light-gathering device, constructing images of the world around you as rays reflect off of the objects in the environment and travel through your cornea.

The Eye

The Cornea

At the very front of your eye, is a transparent, dome-shaped lens called the cornea. It covers and protects the iris, and it plays the first role in providing clear vision. As light rays are reflected off of objects in the environment, they enter the eyes through the cornea. The cornea then refracts, or bends, these rays as they pass through the pupil.

The Pupil

This is the round opening in the center of your eye. The pupil’s size determines the amount of light that will enter the eye, and adjusts in accordance with the dilator and the sphincter muscles of the iris.

The Iris

The iris is the colored part of your eye that divides the anterior, or front of the eye from the posterior, or back of the eye. This part is embedded with small muscles that dilate and constrict the pupil size based on the amount of available light. In bright light, the iris’s sphincter muscles tighten and cause the pupil to contract. In dimming light, dilator muscles will increase the size of the pupil.

The Lens

The crystalline lens is located just behind the iris. As light comes through the pupil, the lens focuses this light onto the retina. As it focuses, the lens changes shape to adjust for the closeness or distance of the objects through a process called accommodation. As we grow older, the lens gradually hardens and the ability to accommodate slowly diminishes.

The Retina

The retina is a sensory tissue that lines the back of the eye. The tissue is filled with two types of photoreceptors, rods and cones, which work to create central and peripheral vision. The retina captures light rays and converts them to electrical impulses. These impulses travel along the optic nerve to the brain, where they are then converted to the images that we see around us.


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