LASIK — Refractive Disorders
Refractive Disorders
In a normal eye, light entering the eye is refracted (bent) first by the eye’s cornea and then by the eye’s natural lens so that it focuses precisely on the retina. The retina is the sensitive tissue on the back of the eye that converts light images into electrical impulses and sends them through the optic nerve to the brain. If the light rays are not focused precisely on the retina, the result is refractive error, or poor vision in the form of nearsightedness, farsightedness or astigmatism.
Nearsightedness (myopia)
Nearsightedness occurs when the eye’s cornea is shaped too steeply, or the eye is too long. Incoming light rays are refracted to a focal point in front of the retina instead of on the retina. This results in distant objects being out of focus, while close objects can be seen clearly.
Farsightedness (hyperopia)
Farsightedness is the reverse of nearsightedness. Instead of a cornea that is too steep, the farsighted eye has a cornea that is too flat, or the eye is too short. Light rays refracted through the cornea converge at a focal point behind the retina. This results in close objects being out of focus while distant objects are more clear.
Astigmatism
Astigmatism is the result of an aspheric (irregularly shaped) cornea that scatters light rays as they enter the eye. An astigmatic cornea has an oblong shape like a football instead of a round shape like a basketball. The result is that there is no single focal point, and vision is blurry both near and far.
Presbyopia
Presbyopia refers to the normal process of aging in which the natural lens inside the eye becomes hardened. As this occurs, the lens loses its flexibility, which makes reading difficult. This usually occurs between the ages of 40 and 50. Everyone experiences presbyopia. The result of this normal process is bifocals for those who wear glasses or contacts, and reading glasses for those who have not needed corrective lenses previously. LASIK surgery will not correct presbyopia.
Correcting Refractive Disorders
Wearing corrective lenses merely treats the symptoms of nearsightedness, farsightedness and astigmatism. The lenses do not correct the refractive error. Those with nearsightedness, farsightedness and astigmatism can benefit from refractive surgery because refractive surgery corrects the error by enhancing the eye’s ability to refract light rays precisely onto the retina. Wolfe Eye Clinic was the first site in Iowa designated as a clinical investigation site for laser vision correction performed with the excimer laser, and today, experienced surgeons perform LASIK at several of the Wolfe Eye Clinic facilities.
