inside a human eye
Inside the eye. Click for more detail.

With our state-of-the-art equipment we can better diagnose eye disorders and make the appropriate corrections for your sight.

Normal Eye

The perfectly focusing eye is an emmetropic eye. Light enters the eye and is sharply focused on the retina. Nerves send the retinal images to the brain and this perfect eye system sees 20/20.

One of the most critical components of your eye is the cornea, the “window” of your eye. The job of the cornea is to bend, or refract, light rays so that they focus on the retina at the back of your eye. Refractive errors occur when the cornea fails to focus light rays precisely on the retina.

visual defects


You may be familiar with the term myopia, also known as near-sightedness. Myopia is the result of an eyeball which is too long, or a cornea which is too curved. In both cases, light rays entering your eye fall short of the retina, and objects in the distance appear blurred. If you have this condition, you are not alone; more than 70 million people in North America have myopia.


Hyperopia, or far-sightedness, is the opposite of myopia. Here, you eye is too short or your cornea is less curved. Consequently, light rays entering your eye fall behind the retina. This results in blurred vision which is worse at near distances than far.


Astigmatism occurs when your cornea is shaped like a football with two different curvatures. Images appear blurred or ghost-like because light rays are refracted unequally. In extreme cases, images both near and far, appear blurred. Many people who have myopia also have astigmatism.


Presbyopia is the inability to focus the eyes at near. Presbyopia generally begins around age 40 as the lens inside our eye loses its ability to change shape. Presbyopia can be quite troublesome if one has to work at a computer all day long. Bifocals help, but because the computer screen is fairly high in our line of sight, bifocals are often too low to be beneficial. Oftentimes, special “computer glasses”, which puts the near correction higher into the line of sight are most beneficial.


Glaucoma is an eye disease caused by increased pressure in the eye that can destroy the sensitive nerve fibers responsible for vision. Usually there are no symptoms related to this disease. It affects approximately 2% of the population over the age of 35.

Many individuals are at a higher risk to develop Glaucoma. Glaucoma is most common in people with a family history of the disease. Patients with systematic disease such as diabetes, anemia, or hardening of the arteries are at higher risk of developing glaucoma. Nearsighted patients are more likely to develop the disease. African-Americans tend to develop glaucoma more often than other racial groups.


The eye’s natural lens is used for focusing near objects and is clear at birth. As we age, the lens begins to lose its clarity. This loss of transparency of the natural lens is called a cataract. A cataract decreases the amount of light that is focused on the retina, resulting in an overall blurriness of images. Having a cataract disturbs vision much like looking through a dirty windshield.

Cataracts are not caused by over using the eyes. The computer has no effect on cataract development. Cataracts progress more quickly with exposure to ultraviolet radiation and cigarette smoking. Recent studies have shown that some vitamins, such as vitamin C may play a role in slowing down the development of cataracts.

Other than the normal aging process cataracts can develop as a result of injury, systematic diseases, and certain drugs such as steriods.

Retinal Detachment

The retina is the thin, light sensitive, lining of the eye. The optic nerve sends the retinal image to the brain where vision occurs. Occasionally, the retina becomes torn and detaches from the internal portion of the eye causing reduced vision, floaters and sometimes flashes of light.

If you experience any of these symptoms, you should contact Dr. Holbert’s office immediately. Retinal detachments are most common in near-sighted individuals. They can also occur after blunt head trauma such as automobile accidents, sporting events or falls. Family history is also a contributing factor.

eye examVision Correction for Nearsightedness

Nearsightedness is a condition where the eye has too much focusing power for its length. Nearsighted correction procedures decrease the focusing power of the eye by slightly flattening the surface of the cornea.

Eye Surgery

Several surgical procedures are described on our Eye Surgery page.