Before the surgery, your surgeon will explain to you the risks and possible complications, and potential side effects, including the pros and cons of having one or both eyes done on the same day. This is the "informed consent" process. Some risks and possible complications include:

• Over- and under-correction. These problems can often be improved with glasses, contact lenses, and enhancements.
   
• Corneal scarring, irregular astigmatism (permanent warping of the cornea), and inability to wear contact lenses. These can cause visual disturbances such as blurred vision, glare, or halos.
   
• Corneal infection.
   
• "Loss of best corrected visual acuity" -- that is, you would not be able to see as well after surgery, even with glasses or contacts, as you did with glasses or contacts before surgery.
   
• A decrease in contrast sensitivity. That means that even though you may have 20/20 vision, objects may be difficult to distinguish in low lighting conditions.
   
• Problems with night driving that may require glasses, contact lenses, retreatment, or may not be fixable. Rarely patients complain they no longer feel comfortable driving at night.
   
• Flap problems, including irregular flaps, incomplete flaps cut off entirely, and ingrowth of cells under the flap.
   
• Corneal ectasia is a condition where the cornea begins to bulge forward after surgery. The risks for this are usually, but not always, identified before surgery. This bulging and thinning of the cornea could require the use of a hard contact lenses or intracorneal rings, or in a more severe case, a corneal transplant to correct.

A small percentage of patients may develop corneal haze, resulting in glare or halos that could require a separate procedure and the use of anti-scarring agents such a Mitomycin applied topically. The risk of this is probably less than 1%.

Please review the patient information provided by these manufacturers.

The following side effects are possible, but usually disappear over time. In rare situations, they may be permanent.

• Discomfort or pain
   
• Hazy or blurry vision
   
• Scratchiness
   
• Dryness
   
• Glare
   
• Halos or starbursts around lights
   
• Light sensitivity
   
• Small pink or red patches on the white of the eye

Remember, even if you see perfectly after vision correction surgery, you may still need reading glasses or bifocal contact lenses once you hit your 40's. This is because your eyes will continue to change as you age, and no one can avoid presbyopia, which occurs when the crystalline lens in your eye becomes larger and stiffer with age. Your distance vision will probably remain crisp, but seeing up close will be more difficult.