Types of laser eye surgery
Laser eye surgery, also called laser refractive surgery, changes the shape of an eye to help improve vision as an alternative to wearing glasses or contact lenses.
Like any surgical procedure, there are risks involved. These should be discussed with the eye surgeon before going ahead with a procedure.
Laser eye surgery to correct vision is not usually available on the NHS.
Different types of laser eye surgery to reshape the cornea include:
LASIK: Short for laser in-situ keratomileusis, this laser eye surgery is used to correct vision in people who are short-sighted, long-sighted and/or have astigmatism (where the shape of the eye is not totally round). During LASIK surgery, vision is corrected by reshaping underlying corneal tissue so that it can properly focus light into the eye and onto the retina. LASIK eye surgery differs from other types of eye surgery in that a flap is made in the outer layer of the cornea so that the underlying tissue can be accessed.
Wavefront-guided LASIK: Wavefront-guided LASIK is a form of LASIK that reduces natural irregularities in the eye and corrects eyesight problems.
PRK: Short for photorefractive keratectomy, this laser eye surgery is used to correct mild to moderate short-sightedness, long-sightedness, and/or astigmatism. During PRK surgery, an eye surgeon uses a laser to reshape the cornea. This laser, which delivers a cool pulsing beam of ultraviolet light, is used on the surface of the cornea, not underneath a flap of the cornea, as in LASIK eye surgery. Therefore, no cutting is required.
LASEK: Short for laser epithelial keratomileusis, this is a newer form of laser eye surgery that combines many of the benefits of LASIK and PRK. However, unlike LASIK and PRK procedures, there is no cutting or scraping of the eye. Instead an epitheal flap is created using a 20% alcohol solution. LASEK surgery is used to treat short-sightedness, long-sightedness and astigmatism.
Is refractive and laser eye surgery safe and effective?
While the results of laser eye surgery are promising, 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 more often than with LASIK eye surgery. If an infection does result from refractive or laser eye surgery, it generally means additional discomfort and a longer healing process.
- Under-correction or over-correction. It is difficult to predict accurately 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 surgery results in under-corrections, which can be adjusted with a second laser eye procedure.
- Poorer 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 surgery, 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 procedure may be needed to correct it. The risk of corneal haze is much less with LASIK 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 procedure is often recommended to achieve more 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 who have had LASIK laser eye surgery or PRK, this can affect and interfere with night driving, especially in people who have large pupils in poor light.
- 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.