The cornea is a part of the eye that helps focus light to create an image on the retina. It works in much the same way that the lens of a camera focuses light to create an image on film. The bending and focusing of light is also known as refraction. Usually the shape of the cornea and the eye are not perfect and the image on the retina is out-of-focus (blurred) or distorted. These imperfections in the focusing power of the eye are called refractive errors. There are three primary types of refractive errors: myopia (nearsighted), hyperopia (farsighted) and astigmatism (general distortion). Glasses or contact lenses are designed to compensate for some of these imperfections. Surgical procedures aimed at improving the focusing power of the eye are called refractive surgery.
In LASIK surgery, precise and controlled removal of corneal tissue by a special laser reshapes the cornea changing its focusing power. Many patients have great success with LASIK surgery while others can tell you some horror stories. The risks of LASIK surgery include:
- Loss of vision.
- The development of debilitating visual symptoms such as glare, halos, and/or double vision that can seriously affect nighttime vision. Under treatment or over treatment. Only a certain percent of patients achieve 20/20 vision without glasses or contacts. You may require additional treatment, but additional treatment may not be possible. You may still need glasses or contact lenses after surgery.
- Development of severe dry eye syndrome. As a result of surgery, your eye may not be able to produce enough tears to keep the eye moist and comfortable. This condition may be permanent.
- Results are generally not as good in patients with very large refractive errors of any type. You should discuss your expectations with your doctor and realize that you may still require glasses or contacts after the surgery.
- For some farsighted patients, results may diminish with age. If you are farsighted, the level of improved vision you experience after surgery may decrease with age. This can occur if your manifest refraction (a vision exam with lenses before dilating drops) is very different from your cycloplegic refraction (a vision exam with lenses after dilating drops).
Be an informed patient: