To be a good candidate for vision correction surgery, you must meet the physical, health and age criteria for the particular surgery. You should fully understand the procedure and be aware of the risks and possible side effects. The general guidelines below may help estimate your suitability for surgery. However, a consultation with a refractive surgeon is necessary to determine whether you are truly a candidate.

Physical, Health and Age Requirements
All refractive surgery procedures have physical, health and age criteria. This includes being at least 18 years old and having:

• healthy eyes;
• a stable eyeglass prescription for at least one year;
• vision within the correctable range of the particular procedure.

Most procedures cannot be performed if you:

• have a history of autoimmune diseases;
• are pregnant or nursing;
• have a history of eye disease or previous eye injury;
• take prescription medications that may affect corneal healing or vision.

Understand the Procedure
Thoroughly read the literature your ophthalmologist gives you, and ask questions if you need further explanation. Be sure to carefully read over the consent form and make sure you understand it before signing. You should also be aware that refractive procedures do not stop the natural changes that occur as the eye ages. Even after refractive surgery you are likely reach a time in your life when you need corrective lenses or eyeglasses. Refractive surgery changes only the front of the eye while the rest of the eye will change naturally as you age. A good example of this is presbyopia, the loss of close-up focusing ability that occurs as most people get into their 40s. People who have had refractive surgery will still develop presbyopia and need to wear corrective lenses or eyeglasses for activities such as reading.

Understand the Risks and Possible Side Effects
In addition to explaining the procedure, your ophthalmologist should also provide adequate information about the risks and possible side effects of the procedure. Typical side effects associated with refractive procedures include:

• Visual aberrations. With some procedures, patients report seeing halos or starbursts around lights at night.
• Dry eye. Symptoms of dry eye are common for many patients following surgery and are usually relieved with the use of artifical tears. The condition usually goes away on its own in the weeks to months following surgery. In some cases, dry eye is a persistent problem, particularly in patients who had dry eye problems prior to surgery.
• Discomfort or irritation. Some patients experience some discomfort during surgery and some eye irritation after surgery.
• Sensitivity to light. Some patients report being more sensitive to light for a few days after surgery.
• Time for vision to stabilize. With some procedures, better vision is experienced immediately after surgery. With other techniques, results can take a few days or weeks.
• Under- or over-correction. The goal of the surgery is to achieve the desired visual result with one surgical procedure, but sometimes under-correction or over-correction may occur. In many cases of under- or over-correction, additional surgery, commonly called an enhancement, is performed after the first surgery has healed to achieve a better result. Less common side effects include:
• Loss of best-corrected vision. Loss of best-corrected vision means that after the procedure, you may not be able to see as well with eyeglasses or contacts as you did with eyeglasses or contacts before the procedure.
• Flap complications. Corneal flap complications are possible with LASIK. When the flap is reattached to the eye after the cornea has been re-sculpted, it is important for the flap to be smooth and clear. Difficulties in creating or repositioning the flap could lead to reduced best-corrected vision.
• Infection or inflammation. Although rare, an eye infection or severe inflammation can cause problems after surgery. The inflammation or infection may need to be treated with antibiotic eyedrops or oral medication.
• Corneal scarring. Corneal scarring is another rare complication of refractive surgery is more often associated with PRK. Refractive procedures have helped millions of people become less dependent on eyeglasses or contacts.

A large part of the success of any procedure depends on your understanding of the procedure and your expectations. With the help of your ophthalmologist, it's ultimately your responsibility to weigh the risks and side effects with the benefits. If you are considering refractive surgery, consult with your ophthalmologist, read all the provided literature, and make an informed decision.