What is commonly referred to as "laser eye surgery" actually refers to two separate procedures. Photorefractive Keratectomy (PRK) was the first procedure developed, followed by the newer Laser-assisted Intrastromal Keratoplasty (LASIK). There are other procedures as well, but they are much less common than LASIK and PRK.
PRK is an older procedure and is rapidly being replaced by LASIK for most patients. PRK involves using a specially tuned laser to burn the surface of the eye until it matches a predefined shape set out by the doctor. Since this procedure affects the cornea (the outer layer of the eye), it is often associated with a great deal of pain. However, the amount of pain varies from person to person, usually high-strength pain killers (codine) will be enough for most people. A more detailed explanation can be found here.
The procedure I undertook was LASIK. This surgery involves cutting a corneal eyeflap, and using the same method as PRK to alter the shape of the layer underneath the corneal flap directly. After the re-shaping takes place, the original flap is replaced. Since there are no nerves where the burning takes place, it does not involve any pain. A more detailed explanation can be found here.
The most realistic risk of the procedure is that you will have to undergo the procedure a second time. Sometimes the doctor will be conservative and under-correct the eyes. In other cases the procedure is successful, but the eyes will regress over time and require some fine-tuning in a second operation. Unfortunately the eyes need to heal before another procedure is done, and there can be several months of wearing interim prescription glasses that is different from the original one. This risk varies depending on your original prescription and the accuracy of the doctor performing the procedure.
The other realistic risk is a slight degradation in nighttime vision. The halo that accompanies bright lights at night will be enlarged for many people, but again it varies from person to person. For the first several months, it may be difficult to drive at night, and to read backlight signs. However this goes away for the vast majority of people after several months.
Another risk is termed "haze" and refers to a slight degradation in clarity, while still retaining good vision. I understand this sounds contradictory, but having experienced this myself, it does in fact occur. You retain 20/20 vision, but everything looks as though it is covered with a thin film, it is similar to a difficulty in focusing. Again, in most cases this usually does not last more than a few months.
With the PRK procedure, there is risk of infection because the surgery is done to the exposed eye. The clinic will provide anti-inflammatory drops that should prevent most problems. With the LASIK procedure there is a risk of shifting the eyeflap, it is critical not to rub your eyes for the first two weeks after the procedure is finished.
There are other risks though. In a small percentage of cases, patients will have to continue to require glasses, often with a different prescription. Also in very few cases the eyes will not be able to achieve 20/20 vision even with. According to my research, there have been no cases of blindness from anyone undergoing laser eye surgery as of this writing.
For a quantifiable estimation of risks, visit this page. Many clinics will tout results much better than this, so these should be considered very conservative.
The main benefit it obvious: you can see! But there are countless benefits that are difficult to quantify or predict before the surgery, so I will list some of my personal favorite post-op benefits.
Sunglasses. Before it was required to get prescription sunglasses made, requiring a several hundred dollar purchase, and was restricted by style and lens type.
Activities. Water-skiing, scuba-diving, swimming, many sports are possible with glasses, but are much better enjoyed with corrected eyes.
Simple Things. The pleasure of waking up in the middle of the night and reading the alarm clock without fumbling for glasses is enormous.
Kissing. It sounds silly, but it is really great not to poke your partner in the face with cold glasses while kissing.
Others. Not experiencing the panic of losing or breaking glasses or contact lenses.
In short, the feeling of having vision unencumbered by an external device is simply wonderful. And you can't quantify that!
Where to go:
If you decide to undergo the procedure, or are trying to decide if it is right for you, choosing your clinic is an important step. Before my surgery I visited three different clinics, and had a radically different experience in each one. The first clinic was The Laser Center (TLC) who actually denied me surgery on the basis that my glasses-prescription had shifted within the last three years. I appreciated that a great deal, so two years later, I visited the same clinic again. However, they were undergoing a complicated change-of-management so I stuck with the doctor instead of the clinic, and visited The Pacific Laser-Eye Center (Pacific). The price quoted to me by Pacific was $4,000 (CAD) for both eyes, much greater that others in the area.
So I visited a local clinic (which I will leave unnamed) for the purposes of comparison. The difference was outstanding. At the local clinic, the price quoted was $1,900 (CAD), but I was appalled at the business practices. The doctor approved me for the procedure before reviewing my medical history, and when I confronted him on this he derided it as unimportant. The success rate that he predicted was much higher than predicted by TLC or Pacific, which I read as shucksterism, not a genuine prediction. So I chose the more expensive clinic with the doctor that I trusted, even though the cost was more than double the cheaper place. If you are investing laser-eye surgery, I strongly encourage you to ensure that choose a reputable clinic. Try to find other people in your area who have had the procedure done, and investigate the various clinics as much as possible.
I chose to have the LASIK procedure, because I preferred the personal risk of rubbing my eyes over the external risk of infection. I visited the clinic on a Thursday morning, and arrived bright and early, and very nervous. First the doctor did a final inspection on my eyes to ensure that nothing had changed in the past days since he last saw me. Then, the assistants took me into a separate room for eye-numbing drops, and awaited my surgery. When the room was prepared I went in the room and laid down underneath the scary-looking laser machines.
At this point I was exceptionally nervous, so they gave me little stress balls to grip. The first step was to cover one eye, and to put a little clamp around the other eye, which felt like a little pinch. This made me unable to blink or move my eyes to any great degree. Then they instructed me to "look at the red light" and the cutting started, as they cut a little circle in my eye around the area. It was quite scary as all of a sudden the little light I was looking at went all fuzzy - the corneal flap was removed! Now the re-shaping was ready to start, and I was strongly reminded to look straight ahead at the red light. Well at this point my blood was pumping so strong and was breathing so hard that they could not continue.
They turned off all the fancy devices, and gave me a sedative, which was great. Thankfully they stopped before I could do any damage, and felt much better after a few moments. Now, they re-attached the eye clamp, and began the re-shaping procedure. The buzzing noise of the laser, and the smell of my own eyes burning was a bit disconcerting, but it only took a few moments, and they re-attached the flap and patched me up to do the other eye. The second eye went without a glitch and I was off the operating table within perhaps 15 minutes. Afterwards, they did some tests to make sure everything was a/ok, and sent me packing. The entire procedure took only 60 minutes including prep time, my freak out, and the actual surgery.
As I have stated throughout this article, my results were a resounding success. Right after the procedure, my eye doctor reported that I had 20/20 vision. Of course, I was patched up at the time, and was terrified of shifting my eyeflaps... but I could see like a normal person. These results were confirmed the next day, and again the following week, month, and ½ year. I returned to work four days after the surgery, and resumed a normal schedule after a week. I'd do it again in a heartbeat.
Note: This topic has been covered before in a different format on Kuro5hin.org, some other excellent testimonials to laser-eye surgery can be found here, here, and here.