 You are not a risk taker. Certain complications are unavoidable in a percentage of patients, and there are no long-term data available for current procedures.

 It will jeopardize your career. Some jobs prohibit certain refractive procedures. Be sure to check with your employer/professional society/military service before undergoing any procedure.

 Cost is an issue. Most medical insurance will not pay for refractive surgery. Although the cost is coming down, it is still significant.

 You required a change in your contact lens or glasses prescription in the past year. This is called refractive instability. Patients who are:

 In their early 20s or younger, 

 Whose hormones are fluctuating due to disease such as diabetes,

 Who are pregnant or breastfeeding, or 

 Who are taking medications that may cause fluctuations in vision, are more likely to have refractive instability and should discuss the possible additional risks with their doctor.

 You have a disease or are on medications that may affect wound healing. Certain conditions, such as autoimmune diseases (e.g., lupus, rheumatoid arthritis), immunodeficiency states (e.g., HIV) and diabetes, and some medications (e.g., retinoic acid and steroids) may prevent proper healing after a refractive procedure.

 You actively participate in contact sports. You participate in boxing, wrestling, martial arts or other activities in which blows to the face and eyes are a normal occurrence.

 You are not an adult.  Currently, no lasers are approved for LASIK on persons under the age of 18.

 Herpes simplex or Herpes zoster (shingles) involving the eye area.

 Glaucoma, glaucoma suspect, or ocular hypertension.

 Eye diseases, such as uveitis/iritis (inflammations of the eye)

 Eye injuries or previous eye surgeries.

 Keratoconus

 Blepharitis. Inflammation of the eyelids with crusting of the eyelashes, that may increase the risk of infection or inflammation of the cornea after LASIK.
 

 Large pupils. Make sure this evaluation is done in a dark room. Although anyone may have large pupils, younger patients and patients on certain medications may be particularly prone to having large pupils under dim lighting conditions. This can cause symptoms such as glare, halos, starbursts, and ghost images (double vision) after surgery. In some patients these symptoms may be debilitating. For example, a patient may no longer be able to drive a car at night or in certain weather conditions, such as fog.

 Thin Corneas. The cornea is the thin clear covering of the eye that is over the iris, the colored part of the eye. Most refractive procedures change the eye’s focusing power by reshaping the cornea (for example, by removing tissue).  Performing a refractive procedure on a cornea that is too thin may result in blinding complications.

 Previous refractive surgery (e.g., RK, PRK, LASIK).  Additional refractive surgery may not be recommended.  The decision to have additional refractive surgery must be made in consultation with your doctor after careful consideration of your unique situation.

 Dry Eyes. LASIK surgery tends to aggravate this condition.

 Some patients lose vision. Some patients lose lines of vision on the vision chart that cannot be corrected with glasses, contact lenses, or surgery as a result of treatment.

 Some patients develop debilitating visual symptoms. Some patients develop glare, halos, and/or double vision that can seriously affect nighttime vision. Even with good vision on the vision chart, some patients do not see as well in situations of low contrast, such as at night or in fog, after treatment as compared to before treatment.

 You may be under treated or over treated. Only a certain percent of patients achieve 20/20 vision without glasses or contacts. You may require additional treatment, but additional treatment may not be possible. You may still need glasses or contact lenses after surgery. This may be true even if you only required a very weak prescription before surgery. If you used reading glasses before surgery, you may still need reading glasses after surgery.

 Some patients may develop severe dry eye syndrome. As a result of surgery, your eye may not be able to produce enough tears to keep the eye moist and comfortable. Dry eye not only causes discomfort, but can reduce visual quality due to intermittent blurring and other visual symptoms. This condition may be permanent. Intensive drop therapy and use of plugs or other procedures may be required.

 Results are generally not as good in patients with very large refractive errors of any type. You should discuss your expectations with your doctor and realize that you may still require glasses or contacts after the surgery.

 For some farsighted patients, results may diminish with age. If you are farsighted, the level of improved vision you experience after surgery may decrease with age. This can occur if your manifest refraction (a vision exam with lenses before dilating drops) is very different from your cycloplegic refraction (a vision exam with lenses after dilating drops).

 Long-term data are not available. LASIK is a relatively new technology. The first laser was approved for LASIK eye surgery in 1998. Therefore, the long-term safety and effectiveness of LASIK surgery is not known.

 Monovision

 Bilateral Simultaneous Treatment

 Compare. The levels of risk and benefit vary slightly not only from procedure to procedure, but from device to device depending on the manufacturer, and from surgeon to surgeon depending on their level of experience with a particular procedure.

 Don't base your decision simply on cost and don't settle for the first eye center, doctor, or procedure you investigate. Remember that the decisions you make about your eyes and refractive surgery will affect you for the rest of your life.

 Be wary of eye centers that advertise, "20/20 vision or your money back" or "package deals." There are never any guarantees in medicine.

 Read. It is important for you to read the patient handbook provided to your doctor by the manufacturer of the device used to perform the refractive procedure. Your doctor should provide you with this handbook and be willing to discuss his/her outcomes (successes as well as complications) compared to the results of studies outlined in the handbook.

 During surgery. Malfunction of a device or other error, such as cutting a flap of cornea through and through instead of making a hinge during LASIK surgery, may lead to discontinuation of the procedure or irreversible damage to the eye.

 After surgery. Some complications, such as migration of the flap, inflammation or infection, may require another procedure and/or intensive treatment with drops. Even with aggressive therapy, such complications may lead to temporary loss of vision or even irreversible blindness.

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