Understanding Your Vision
Before you can understand refractive surgery you must understand the basics of vision disorders and refractive errors. Myopia (Nearsightedness), Hyperopia (Farsightedness), Presbyopia (Bifocals), and Astigmatism are the main refractive errors that cause people to need glasses, bifocals or contact lenses. Each case brings separate issues and requires specialized treatment. Technology has evolved to impact each of these refractive errors.
Nearsightedness
Nearsighted patients typically have trouble seeing at distances and often require glasses for driving or everyday functionality. Nearsighted patients are typically great candidates for LASIK eye surgery even if the patient has existing astigmatism. With a myopic patient the excimer laser is used to reshape the cornea. The laser actual decreases the amount of corneal tissues, thus changing the shape of the cornea and the refraction.
Farsightedness
Farsighted patients typically have trouble reading or seeing things up close and require reading glasses. Individuals over the age of 40 will often start to experience the first signs of naturally occurring loss of close vision. Refractive Surgery can correct farsightedness. Some modern refractive surgery for decreasing farsightedness would be hyperopic LASIK, Laser Thermal Keratoplasty (LTK), conductive keratoplasty (CK), or multifocal IOL refractive lensectomy.
Astigmatism
Astigmatism is a common vision condition where the corneal surface is not evenly shaped, causing one to see ghosting or shadowing of images. With astigmatism, the cornea is not a perfect sphere, like a basketball, but is steeper in one direction and flatter in the other, like a football. Astigmatism can occur alone but is most often combined with nearsightedness or farsightedness.
Presbyopia
Presbyopic patients suffer from both near and far vision loss. They typically use bifocals to function in everyday life. There are options for the correction of presbyopia to a certain extent. There is no definite correction to solve the entire presbyopic disorder but there are methods that can deal with near or far vision.
Monovision
Monovision is a type of correction that corrects one eye for close and the other for distance vision. There are also some new multifocal IOL lenses that correct both far and near vision but do not guarantee perfect 20/20 vision.
