Refractive Errors and Laser Vision Correction

How does laser vision correction change the way I see?

When light enters the eye, it is bent (focused) primarily by the cornea, which is a clear, strong tissue that permits light to pass through the eye. The iris, the colored part of the eye, works like a camera shutter, expanding or contracting to accommodate varying degrees of light intensity. The light rays pass through the opening in the iris, or pupil, then through the lens, thereby completing the refractive process.

Lastly, the retina, with its rods and cones, is the photosensitive membrane or “screen” at the back of the eye that transforms light into sight by converting it into electrical impulses. These impulses are sent via the optic nerve to the brain, which interprets these impulses as images.

Refraction, the term used to describe the way light is focused by your eye, depends on three elements: the curvature of the cornea, the power of the lens, and the length of the eye. When these elements are correctly proportioned or arranged, light is properly focused on the retina and one experiences good vision. If not, as is the case for a large percentage of the world’s population, then one is said to have a refractive error. Through Laser Vision Correction, the shape of the cornea can be adjusted so that light will properly focus on the retina, resulting in clear vision. Contact our laser vision correction practice in Chevy Chase, Maryland, to learn more.

There are basically four types of refractive errors:

Myopia (Nearsightedness)

A myopic eye has too much focusing power. Light passing through the eye falls in front of the retina due to excessive curvature of the cornea, or because the eyeball is too long. When a cornea has excessive curvature, it is said to be too “steep.” Individuals with this irregularity are said to be nearsighted because objects seen at a distance are blurred, while those in near range can be seen clearly.

The excimer laser can be used to reshape, or flatten, the cornea of a myopic eye to permit light to focus on the retina, instead of in front of it. If you are nearsighted, Laser Vision Correction may be the answer! Contact our Chevy Chase, Maryland location to schedule a consultation.

Hyperopia (Farsightedness)

A hyperopic eye has insufficient focusing power. Light passing through the eye falls behind the retina because the cornea does not have enough of a curve to properly refract light, or the eye is too short. People with this irregularity are said to be farsighted because they are better able to focus on far away objects than on objects close to them.

The excimer laser can be used to reshape, or steepen, the cornea of a hyperopic eye to permit light to focus on the retina instead of behind it. If you are farsighted, Laser Vision Correction might be a viable solution! Contact our office in Chevy Chase, Maryland location to see if you are a candidate.

Astigmatism

An astigmatic cornea lacks a uniform, round surface; it has two different curvatures. This results in the inability to clearly focus all images on the retina. Light rays entering the eye are distorted, which blurs vision along a certain meridian or axis of the cornea. Think of it this way: normal corneas are round like baseballs; astigmatic corneas are elongated, like footballs. Astigmatism is very common and is often present in individuals with myopia or hyperopia.

The excimer laser can be used to reshape the cornea of an eye with astigmatism to give it a more uniform surface. If you suffer from astigmatism, laser vision correction could give you clear vision. Contact our Chevy Chase, Maryland location to schedule a consultation.

Presbyopia

As we get older, we gradually lose the ability to change focus from distance to near. This is a gradual change throughout life but it is usually not noticeable until the mid-forties. This condition is called presbyopia, and it makes reading and other close work increasingly difficult. As this occurs, people who have been nearsighted or farsighted begin to wear bifocals. People who have never worn glasses begin to wear reading glasses for close-up work.

The excimer laser is not used to treat this condition because reshaping the cornea will not affect the aging changes occurring to the lens inside the eye. However, a laser vision correction option called monovision is available. With this type of treatment, the surgeon fully treats one eye for distance, and the other eye for near vision. This laser vision correction treatment leaves one slightly nearsighted eye for good near vision without glasses. Please see the monovision section for more information this form of Laser Vision Correction available at our facility in Chevy Chase, Maryland.