Surgical Vision Correction

LASIK combines two techniques of surgery to correct refractive error. First, a microkeratome creates a thin flap in the cornea. Next, an excimer laser sculpts the underlying cornea into a new shape to correct the refractive error. The flap is then repositioned and adheres on its own without sutures after only a few minutes. Eye drops are placed in the eye to facilitate the healing process. Vision recovery typically is rapid, and there is little or no post-operative pain.

Is Refractive Surgery for me?

You are probably a good candidate for refractive surgery if none of the below applies to you:

You required a change in your contact lens or glasses prescription in the past year.

This is called refractive instability. Patients who are younger than 21 years of age, or whose hormones are fluctuating such as women who are pregnant or breastfeading, are more likely to have refractive instability and should discuss the possible additional risks with their doctor.

You have an active disease or are on medications that may affect wound healing.

Certain conditions, such as autoimmune diseases (e.g., lupus, rheumatoid arthritis), immunodeficiency states (e.g., HIV) and uncontrolled diabetes, and some medications (e.g., retinoic acid and steroids) may prevent proper healing after a refractive procedure.

It will jeopardize your career.

Some jobs prohibit certain refractive procedures. Be sure to check with your employer/professional society/military service before undergoing any procedure.

You actively participate in contact sports.

You participate in boxing, wrestling, martial arts or other activities in which blows to the face and eyes are a normal occurrence.

You are not an adult.

Currently, all refractive procedures are only approved on persons over the age of 18. Many patients will need to wait until 21 years of age for their eyes to stabilize.

About Refractive Surgery

Refractive surgery includes several surgical procedures designed to eliminate or reduce the need for glasses or contact lenses. These procedures correct refractive errors by changing the focus of the eye. Common procedures such as LASIK and PRK do this by reshaping the curve of the cornea (the clear front window of the eye) to move the point at which light is focused onto the retina (light-sensitive tissue lining the back of the eye). Phakic Intraocular Lenses like the Visian ICL™, place an artificial lens inside the eye to more accurately focus light onto the retina. Refractive Lensectomy involves removing the crystalline lens and replacing it with a lens implant in order to change the power of the lens.

Refractive Errors

The shape of your eye determines how well your vision can focus. Light rays enter the eye through the clear cornea, then through the pupil and the lens. In a normal eye the light rays are focused onto the retina, a light-sensitive tissue lining the back of the eye. Signals from the retina are sent through the optic nerve to the brain, where they are interpreted as the images we see. Refractive errors exist because the curvature of the eye is mismatched to the length of the eye and light rays cannot focus properly on the retina. It is technically very complicated to change the length of the eye (although it has been attempted) so refractive surgery procedures either change the shape of the front surface or add a lens to improve the focus.

Myopia (Nearsightedness)

Myopia is the most common refractive error, affecting more than one in four people in North America. Myopic patients are nearsighted; they see close objects more clearly, but distant objects are blurry or even indistinguishable. Myopia occurs when the eye is too long or the cornea is too steep. As a result, light rays entering the eye fall in front of the retina instead of directly on it. The condition can be inherited and usually starts in childhood and stabilizes in the late teens or early adulthood. Traditionally, corrective lenses such as eyeglasses or contact lenses have been prescribed to refocus light entering the eye directly onto the retina.

Hyperopia (Farsightedness)

Hyperopic patients are farsighted; they can focus on more distant objects, but close-up objects appear blurry. Hyperopia occurs when the eye is shorter than normal or the cornea is too flat. As a result, light rays are not focused by the time they reach the retina. In young people, the natural lens can sometimes correct the focus in hyperopic eyes. With aging, the natural lens loses this ability and the vision blurs. This is why many hyperopic patients do not become aware of their condition until they enter their 20s or 30s.

Astigmatism

Astigmatism occurs when the curve of the cornea, and sometimes the lens, is uneven-steeper in one direction than the other-like a football or the back of a spoon. Almost everyone has some degree of astigmatism, but for some the uneven curve causes light rays to focus on many points in the eye and distorts both close and far vision.

Presbyopia

Presbyopia is the age-related loss of close-up focusing ability. When we are young, our eye's lens is soft and flexible and can change shape easily, allowing the eye to focus on objects both close and far away. As people enter their 40s, the lens becomes less flexible and is unable to focus on close-up objects. Initially the blurring is worse in dim light, which is why many people first realize they have presbyopia when they have difficulty reading a menu. Later, the fine print in newspapers, magazines and phone books appears blurry. Near vision is most often corrected with reading glasses or bifocals, but refractive surgery can be used to create monovision in people who want correction for close-up vision. See the section on "Monovision" for more information.

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Find out more about our Surgical Vision Correction specialists, including their practice philosophies and special interests:

• Patel, Niraj MD, FACS