Orthokeratology or Ortho-K is a safe non-surgical procedure designed to improve natural vision without corrective lenses. Most mild astigmatic, hyperopic, or farsighted conditions can be reduced dramatically, or even eliminated. Even patients, who are extremely myopic, or nearsighted, can achieve dramatic improvements that will allow them to have functional vision without lenses. Ortho-K is sometimes referred to as orthodontics for the eyes because it gently reshapes the cornea through a series of custom fitted lenses. Because the tissue of the cornea is soft and moldable, the result is corrected vision. Retainer lenses must be worn on a part-time basis to maintain the optimum shape of the cornea.
The Orthokeratology procedure involves thorough eye examinations, lens changes and/or lens modifications as needed until the desired results are obtained. The process can take from six weeks to a few months or longer to complete, depending on the severity of the problem. The result is dramatically improved vision with retainer lenses being worn on a limited basis, sometimes only at night during sleep, to maintain the new shape of the cornea.
To really understand how Ortho-K changes your vision, you must first understand how your eye works.
The primary function of your eye is to focus light. Your eye works like a camera. The cornea, at the front of your eye, provides most of the focusing power. The lens, inside your eye, provides the fine tuning and reading ability.
The retina, at the back of your eye, acts like the film. For you to see clearly, light rays must focus precisely on the retina. You need glasses and contacts when the eye cannot properly direct light rays on the retina. People who wear corrective lenses might have one of the following problems.
Myopia (near objects are clearer than distant objects) occurs when your eye is too long in relation to the curvature of your cornea. Light rays entering the eye come to a focus in front of the retina, producing a blurred image.
Hyperopia (distant objects are clearer than near objects) occurs when your eye is too short in relation to the curvature of your cornea. Light rays entering the eye come to focus behind the retina, producing a blurred image.
Astigmatism occurs when your cornea is too oval. Usually the cornea is shaped like a baseball, but when there is an astigmatism, the cornea is shaped more like a football. The result is unequal bending of light rays entering the eye. This produces different focal points and results in distortion.