laser eye surgery statistics

laser eye surgery statistics

… I am afraid that it will change my eyes. What are the statistics on:
failures resulting in worse vision than before?
failures resulting in blindness in one or both eyes?
amount of people who experience permanant side affects?

Also, does the surgery alter eye colour or intensity in any way? Does it make the eye colour duller or less varied or does an eye before and after the surgery look exactly the same? Can someone also explain why scarring doesn’t occur when eye tissue is burned away – a laser burn at any other place on the body would scar – why not the eye?

Let me try to answer your questions in order:

Failure resulting in worse vision? Nearly none. Today’s laser surgeries are very safe and effective. We know more about the eye than ever before. As such, patients are thoroughly screened prior to surgery to minimize complications (corneal ectasias, bacterial infection, etc.). Note that I did not say that there are no complications. In rare instances, complications could potentially lead to decreased vision, even blindness. Examples are extreme bacterial infection of the flap/cornea, free flaps that are damaged during surgery (rare, but has been documented), diffuse lamellar keratitis (stages 3 or 4), etc. These are rare occurances, and some studies put this risk around 0.5%.

More commonly, minor complications such as a dislodged flap, wrinkled flap, epithelial ingrowth, or regression towards your old prescription occurs. Without the eye jargon: little things that the eye surgeon can easily take care of.

Does the surgery alter eye color or intensity? No. Eye color is due to pigmentation of the iris, which is internal, while surgery changes the cornea, which is external.

Scarring? Yes and no. The most visible scar is only going to be visible to your eye doctor when he/she uses a biomicroscope to look at your eye. The amazing thing about eyes is their ability to heal. The tissue that is cut will “reconnect” to a degree; however, that central part of the cornea will never be as strong as it once was. Should you get poked just right in the eye, etc. that flap could pop up or dislodge. This is why patients are not recommended to return to swimming or basketball or other vigorous activities for a short time after LASIK. Note that this doesn’t just spontaneously occur – it would take some amount of force for the flap to dislodge after healing. With LASIK, the tissue is not burned (coagulated) as in some other surgeries (like with the retina). Rather, the tissue is ablated by a laser. Each laser is different – excimer lasers, like those used in lasik, PRK, and other refractive surgeries work by photoablation and do not burn the eye.

After laser surgery, you can be expected to need a lot of artificial tears. The ocular surface needs to stay moist (and the nerves in the cornea that are responsible for the tear reflex are damaged temporarily by the surgery). Also, eyedrops that decrease inflammation (corticosteroids) and an antibiotic drop will be prescribed.

To wrap up: without actually evaluating you it would be hard to say if you are a good candidate for laser surgery. Age, glasses prescription, and ocular and systemic health need to be evaluated before undergoing laser surgery.

There is more than one procedure for laser refractive surgery – LASIK (laser-assisted in-situ keratomileusis) being the most sought after due the most promising outcomes of crystal-clear vision. Other procedures include PRK (photorefractive keratectomy), lasek (laser-assisted sub-epithelial keratectomy), and epi-LASIK (epithelial laser-assisted in-situ keratomileusis). Each surgery is a little different and offers varied visual outcomes. There is even variation within LASIK procedures.

Typically, the best (and most costly) procedure is custom platform LASIK with the flap being cut by a laser (a femtosecond laser such as IntraLase). A custom platform allows computerized calculation of your vision after LASIK to a more thorough degree than less-expensive options. (This is typically marketed as “blade-free” LASIK). Note that the choice of flap-cutting tool does not enhance the outcome of the procedure – blade (microkeratome cut) or lasered (laser cut) flaps both work the same. It is the platform (custom or traditional) that is actually responsible for the extreme clarity.

I know it was lengthy, but I hope this helps a bit.

The website allaboutvision gives a decent look at laser eye surgery pros, cons, and procedures.

http://www.allaboutvision.com/visionsurgery/

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