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    An Overview of Refractive and Laser Eye Surgery

    Are Refractive and Laser Eye Surgeries Safe and Effective?

    While the good results of laser eye surgeries have been well documented, there are possible side effects. It is important to keep these side effects in mind when considering refractive or laser eye surgery.

    • Infection and delayed healing. Infection resulting from PRK occurs in only one-tenth of 1% of patients. For LASIK eye surgery, this number is even smaller. If an infection does result from refractive or laser eye surgery, it generally means added discomfort and a longer healing process.
    • Undercorrection or overcorrection. It is difficult to predict with absolute accuracy the success of refractive or laser eye surgery until the eye has healed properly. Patients may still need to wear corrective lenses even after laser eye surgery. Often surgeries resulting in imperfect corrections can be adjusted with a second laser eye surgery, called laser enhancement.
    • Worse vision. Very rarely, the best achievable vision with or without glasses is worse after refractive or laser eye surgery than it was before. This could 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. It usually has no effect on the final outcome of vision after laser eye surgery and can only be seen through an eye exam. 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 surgery than it is with PRK. Also, the use of a medication called mitomycin during PRK surgery is very effective at preventing haze after surgery.
    • Regression. Sometimes the effects of refractive or laser eye surgery decrease over a period of months or years. When this happens, a second surgery is often recommended to achieve optimal 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. The use of wavefront technology and larger laser optical zones has dramatically decreased the incidence and severity of glare and halo after laser refractive procedures
    • Flap damage or loss. This is a rare risk factor with LASIK laser eye surgery only. Because in LASIK there is a hinged flap on the central cornea, the flap may require repositioning during the first few days after surgery or, very rarely, after a severe direct injury to the eye.

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