The cornea is the smooth, clear window of the eye in front of the colored iris that helps bend light rays so they focus directly on the retina, the light-sensing layer of cells at the back of the eye. If the corneal surface is rough or cloudy, the rays of light do not focus properly on the retina and images are blurry. Until recently, ophthalmologists (Eye M.D.s) treated rough corneas by scraping them smooth with a surgical blade, while cloudy corneas required a partial or full corneal transplant. Now, phototherapeutic keratectomy (PTK) is an option.

PTK is an excimer laser surgical procedure that removes roughness or cloudiness from the cornea by using a cool beam of light to evaporate tissue. The principal advantage of laser surgery over conventional surgery is that the laser is able to create a smoother corneal surface than a blade and smaller amounts of tissue can be removed.

Potential complications after PTK include poor wound healing, excessive corneal flattening resulting in farsightedness, and irregular astigmatism or poor vision that cannot be corrected completely with glasses.

(c) 2007 The American Academy of Ophthalmology