Worse vision. Occasionally the vision through corrective lenses is actually worse after refractive or laser eye surgery than it was before. This may be a result of irregular tissue removal or excess corneal haze.
Excess corneal haze. Corneal haze occurs as a part of the natural healing process after some refractive or laser eye surgeries, including PRK. It usually has no effect on the final outcome of vision after laser eye surgery and can only be seen through an eye examination. Occasionally, however, this haze may affect a patient's vision. A second refractive or laser eye surgery may be needed to correct it. The risk of corneal haze is much less with LASIK laser eye surgery than it is with PRK.
Regression. Sometimes the effects of refractive or laser eye surgery gradually disappear over a period of several months. When this happens a second surgery is often recommended to achieve permanent results.
Halo effect. The halo effect is an optical effect that occurs in dim light. As the pupil enlarges, the untreated area on the outside of the cornea produces a second image. Occurring sometimes in patients having LASIK laser eye surgery or PRK, this can affect and interfere with night driving, especially in patients who have big pupils in dark conditions.
Flap damage or loss. This is a risk factor with LASIK laser eye surgery only. Instead of creating a hinged flap on the central cornea that can be closed, the entire flap may detach, risking permanent damage to the cornea.
Refractive and laser eye surgeries require healthy eyes that are free from retinal problems, corneal scars, and any eye disease.
Beyond side effects, there are other questions to ask before deciding on refractive or laser eye surgery, such as: