Lol! Nice, Mr. Wallace... He has a point, tho... As one of those laser-victims myself, and having a physiology degree, I know a li'l about this.
PRK Laser surgery uses a CO2 laser beam to blast off bits of the cornea, reshaping that optical focussing surface to, in effect, make that magnifying glass a little 'weaker'. (the problem us near-sighted folks have is that the image focusses just in front of the retina... the 'lens system' is a wee bit too strong vs length of eyeball). By thinning and 'weakening' the cornea a little, the image now hits bang-on, and voila!
Problem.... the cornea has been thinned somewhat. In order to maintain their lovely round shape, eyeballs are fluid-filled sacs with a decent amount of PRESSURE inside! (ever disect cow eyes in highschool science? Squirt!!) When this procedure was new, there was some concern that *IF* a cockpit depressurized (no fear of rapid de-press in biplanes!), the significant pressure inside eyeball COULD POSSIBLY cause the eye to 'bulge' slightly where it has been weakened. Think week-old balloon... often shows a weak-spot. Even the tiniest deformation in that front surface of the eye would COMPLETELY distort one's vision (the cornea actually does a lot more light-bending than does the internal Lens, which only fine-tunes things a bit). As a Commercial Multi-IFR pilot, I can attest that suddenly distorted vision would be, how you say... NOT Cool!
Forces was taking a cautious approach that this would be a bad way to lose $30M jets, and so regarded all eye-surgery as a dis-allowing factor until they had enough long-term data on enough guinea-pigs like me (ticked the box on the form at the clinic to share my data with Health Canada, Forces, other intersted parties, etc) to prove beyond a doubt that this was not a legitimate fear. I had the surgery back in '94, applied as DEO Pilot in '96 and was declined bcz of this. 17 years later I've re-applied now that it's allowed, have V1 score, and on my way thru the system.
As far as I know, PRK (Photo-Refractive Keratectomy) is the *only* surgical corrective procedure Forces are accepting - SO FAR. Still some fear that the 'cutting' involved in some other techniques (LASIK and others) will cause scarring along the cut lines and long-lasting (permanent?) weak spots on the cornea that may never regain their full strength. Who knows... in 10-15 years, some other techniques may be tested to death and then accepted.
This is all just AS FAR AS I KNOW, based on my personal experience, schooling, and what I remember being told by Opto's, Civilian Pilot Medical Examiners, etc. As always, there are FAR more official sources than Milnet! lol Best to go straight to the source...
p.s. Several years before my surgery, my older brother had it's predecessor at same clinic. Called RK (Radial Keratotomy), whereby the same effect was acheived by cutting several deep slices (80-90% straight down thru cornea, freehand with a diamond-tipped scalpel!!!) in an asterisk pattern, which causes the whole cornea to heal slightly 'flatter'. YEESH!
'Greg.
