Refractive Errors

For the eyes to function properly, light has to be refracted, or bent, by the cornea and the lens. A refractive error is considered to be a defect in the shape of the eye that causes improper bending of the light. This error can result in blurred or fuzzy vision.
Refractive errors present in four types: 
  • Myopia or nearsightedness
  • Hyperopia or farsightedness
  • Astigmatism or blurred vision on objects that are both near and far
  • Prebyopia or difficultly focusing on objects nearby

A patient can have any combination of these errors, and they can change over time. The term 20/20 is used to describe normal vision, defining the ability to see objects clearly at 20 feet away. When it becomes more difficult for a patient to see objects that are far away, the measurement increases in such a manner that a person with 20/80 vision must be 20 feet from an object that a person with normal vision sees at 80 feet.
Treating Refractive Optic Errors
Refractive errors are commonly treated with glasses or contact lenses. Surgeries have also become increasingly popular with a procedure called LASIK. Most surgical techniques will either change the curvature of the cornea or use an artificial lens to correct vision.