You should only consider laser correction if your prescription has been stable for several years. If you prescription is changing at all then there is no point in having your eyes corrected because they will change again.
Your eye surgeon is supposed to assess your suitability for laser correction and to hand-hold you the whole way through. It takes about 6 months before the process is complete and you should be able to go back at any time for minor adjustments (not more laser surgery) and hand-holding.
My guy was pretty well known and respected in the medical world and had heaps of publications and did lots of ersearch. I would not gop to some cheap shit clinic that just takes your money and churns you through.
With PRK they use a blunted scalpel to remove the epithelium, which is the outer surface of the eye. They then clean the remaining tissue off before lasering. It is quite a strange feeling to have two 6 foot, 80kg guys leaning on your eyeball poking it with a blunt scalpel and scrubbing away at it with a piece of gauze. The blunt scalpel cuts the epithelium but does not damage the underlying cornea.
Before all this you are given a couple of tranquilisers and cocaine drops to the eyes so you feel no pain and are full of peace and happiness to all men.
They then laser you while you keep your eye focussed on a dot of red light. Of course, the red dot seems to be skating all over the place. There's a smell like someone is burning the bacon. That's your eyeball being lasered. They have to monitor the humidity in the room and the moisture content of your eye so that you get the right quality of burn.
When it's all finished they pop the flap of ephithelium back on and bandage your eye. The next morning you take the bandage off and you can see. Over the next 6 months you have steroid drops which are used to manipulate the internal pressure of your eyeball so that yuo end up with the best possible result. You vision can vary a bit during this time.
Lasik is the same except they cut through the epithelium and straight into the cornea and just fold the flap over. Once they have finished lasering they just drop the flap back into place and you can see straight away. You still need the after care and adjustment with the steroid drops.
The older system just laser out a divot from the middle of the cornea which focuses light on the centre of your retina. In low light conditions when your iris opens wide up you can get light around the edges of the corrected bit which causes back-scatter. Your vision is less crisp in low light. Once it get's back to darkness the back-scatter stops and yuo have razor sharp vision again.
The new lasik systems actually re-shape a much bigger section of the cornea and reduce the back-scatter effect in low light. Thet can also correct astigmatism.