Dave,
Yes, what I got is Lasik. I'm an engineer, and I've been watching the tech for eye correction for 15+ years, and I will echo, DO NOT GET Radial Keratectomy or PRK unless your really understand the implications! When last I looked, this involved (for RK) radial incisions directly through the surface of the cornea, like spokes of a wheel, or laser ablation of the surface of the cornea (PRK). It is done with either a scalpel, or a laser, respectively.
PRK (Photorefractive Keratectomy) is different in that rather than incisions, the surface of the cornea is sculpted by the laser. The outer layer of the cornea must then re-grow, sometime unpredictably, and usually slowly.
The RK technique was used extensively in Russia for a while, and done in an assembly line fashion. It depends on the cut causing the cornea to collapse and flatten, thereby reducing myopia. At the time, it relied primarily on the skill of the scalpel wielder. I suppose lasers can do the job more accurately, but...
This method has some major problems:
1) It is very difficult to predict how much a particular cornea will collapse and flatten in response to the incisions, and
2) The incisions through the cornea leave very subtle scar tissue, which causes a star shaped refraction around lights at night. If you have astigmatism, something similar may already be familiar to you. When you remove your glasses at night and look at a light, astigmatism will cause the out of focus light blob to look egg shaped. The RK will make a light look like a sharp multi pointed star.
3) Progressive changes to the eye are often noted, leading to irreversible over-correction, as well as (with RK) weakening of the cornea.
4) The re-growth of the corneal surface can be unpredictable and take a while.
Caveats:
I gave up on RK and PRK as too crude a choice for me, so I may be uninformed about recent advances, but I imagine the problems I mentioned are still significant.
One other reason RK / PRK may be one's only choice (I think, check this out yourself): Blue eyed people may have eyes with two significant features that may counter-indicate Lasik, which are thin corneas, and pupils that dilate widely at night. My wife couldn't get Lasik for both reasons. I believe PRK doesn't require the cornea to be as thick as Lasik (I may be wrong about this) I'll explain further.
Lasik:
The method used a microkeratome to (sorry if this sounds rough, but the valium provided made the whole procedure rather curious, a-la alien close encounter examination) cut back a flap of the cornea. The laser then ablates very small plugs of interior corneal tissue, in a pattern determined by the pre exam. The flap is then gently smoothed back over the formerly flat, now precisely ablated concave corneal section. The advantage of the flap is that it gets the scar tissue out of the optical path. Corneal surface layers aren't as likely to heal well as the interior layer.
The corneal thickness and pupil dilation come into play thus:
The depth of ablation depends on the level of correction required. 20/500 requires a deep ablation, 20/100 a relatively shallow ablation. I believe a typical cornea is about 500 um thick (1/2 mm), and there must be ~200um for the flap, and ~150um for under the ablation, leaving about 150 um for correction.
The diameter of the ablation is driven by nighttime pupil dilation. Small dilation, small ablation diameter. Since the cornea is nominally spherical, the demand for a larger diameter ablation also drives a DEEPER ablation. This should be clear with a little thought.
So, my procedure was sort of ideal, even though I had astigmatism and about 20/550. I have brown eyes, which typically mean thick corneas and small nighttime dilation. Thick cornea means about 625 um. So if need be, I can return for further correction, since I still have 500um+ to work with. My wife was the opposite, blue-gray eyes, thin corneas, large nighttime dilation, which makes her very cute, but not when she found out she couldn't get the surgery too.
If the Lasik is your choice, just remember to hold absolutely still. I practiced not breathing for the 45 seconds it takes per eye, and I'm convinced it made a difference. The laser can stop itself if it detects you've moved, but why test that feature?
Also, I used to wear contacts, which I suspect contributed to some major discomfort (felt like a lot of sand in my eyes) for about 4 hours afterward. I laid down, let my eyes tear, but NO RUBBING, no matter what! After that 4 hours, I COULD SEE! AMAZING!
If any of this is unclear, please let me know right here. I will certainly try to respond if I can, but your Dr. should be much more informative. I will check this thread again today.
One word on Lasik / PRK providers. Some will do the surgery in spite of counter-indications. My Dr. was in Montreal, and flatly refused to do my wife's eyes; this is a man with integrity, which in my opinion, is sorely lacking these days. I recommend these guys to everyone who asks. I heard a story of a man who should have been denied the surgery (done elsewhere), but wasn't, leaving him essentially night blind. He expressed, as I recall, huge regret.
Demand objectivity and integrity, its your money, but more importantly, your sight! No compromise here! Apologies in advance if any of this misses the mark, but I wanted to get it out.
Best Regards,
Bryan
