i conside myself a healthy person, have never had any major complications of any type. i've been to two places for lasik and have been rejected by both. they say that my corneas are too thin and thus not a good candidate for lasik or prk. this is my latest prescription by my optometrist(wchich has been very stable for the last three years); O.D. -4.25 -0.50 X 032, O.S. -5.00 -1.00 X 157 . the thickness of my corneas are 460 microns and 480 microns. i din't ask about the diameter of my pupils. but have never been told that they are big, or that it is one of the collaborating reasons for me not being a good candidate. should i give up my quest for corrective eye surgery?

A minimum of 250 microns of corneal tissue must remain untouched for a healthy eye to remain stable. More is always better.

A Lasik flap will be from about 100-160 microns thick. Flaps made with the femtosecond laser (IntraLasik) can be made thinner with greater reliability than flaps with a mechanical microkeratome, but they are reasonably compatible.

Conventional laser ablation refractive surgery treating a 6.0mm area of the cornea will remove 12 microns of tissue for every 1.00 diopter of refractive error. Your worst eye has about 5.50 D of total refractive error, so this would be 12x5.5 or 66 microns.

If you had IntraLasik with a 100 micron flap and 66 microns of tissue removal, you would have about 314 microns of untouched tissue. This is within the margin considered safe. If you were to have Lasik with a mechanical microkeratome and a flap of 160 microns thick, then you would have only 254 microns remaining untouched and that simply is too close for comfort. It would appear that a thin flap Lasik or IntraLasik would be a possibility.

Surface ablation techniques of PRK, LASEK, and Epi-Lasik do not require the 100-160 micron flap, so these techniques would all appear to be viable.

If the treatment zone is larger than 6.0mm, then the ratio of microns of tissue removed for every diopter of refractive change is greater. At a 7.0mm treatment, about 18 microns of tissue are removed for each diopter of change, yielding about 99 microns of tissue removal in your worst eye and making Lasik nearly impossible but IntraLasik a narrow possibility.

Wavefront-guided ablation requires more tissue removal per diopter of treatment, but the exact amount is impossible for me to predict. This will be determined by the wavefront analysis prior to surgery. Your doctor would be able to determine if wavefront would be okay.

If your corneas are healthy and if your pupils are not terribly large, it would appear that you may be an appropriate candidate for a thin flap Lasik, thin flap IntraLasik, or any surface ablation technique, however only a comprehensive examination from a competent surgeon can determine if you are actually a candidate.

You should read:

Lasik and Pupil Size
http://www.usaeyes.org/lasik/faq/lasik-pupil-size.htm

Custom Wavefront Lasik
http://www.usaeyes.org/lasik/faq/lasik-wavefront-custom.htm

Calculate Lasik Ablation
http://www.usaeyes.org/lasik/faq/lasik-calculate-ablation.htm

IntraLasik
http://www.usaeyes.org/lasik/faq/intralase-intralasik.htm

Glenn Hagele
http://USAEyes.org
Lasik Patient Advocacy & Surgeon Certification

I am not a doctor.

Don't listen to that crap that Intralase may be your answer. If you have thin corneas, they will be even flatter after surgery and you can forget about seeing good at night again. After Intralase, I can't watch tv unless the room is brightly lit. An LED on a clock looks like it is smeared with finger paint. I see 3 moons and two streetlights where there should be one. That is what Intralase did too healthy corneas so if you have been told that you are not a good candidate, thank God for honest doctors and wear glasses.

We have had very good results with your type of eye picture [thin cornea]. We use a 90 micron head which makes a 90 micron flap, in our patients with thin corneas. Using our Wavelight Allegretto Eye Q [400 Hz] laser system, working your calculations, you should be left with between 290 to 300 micron cornea after LASIK. Alternatively, Epi LASIK would be a good option as well.
However, we are based in india.
please check www.lasikindia.in
Dr Shroff, MD

Unfortunately, the Wavelight Allegretto Eye Q [400 Hz] laser is not yet available in the US. I understand that this is an exceptional laser and is somewhat compareable to the Alcon LadarVision 6000 and the Bausch & Lomb Technolas 217z Zyoptix, which are available in the US.

Glenn Hagele
http://USAEyes.org
Lasik Patient Advocacy & Surgeon Certification

I am not a doctor.

I was told that I would probably need cornea transplant if I had lasik or epi lasik. Very depressing indeed but I would like to know what my other options are because I really don't like wearing glasses all the time but I think God for honest doctors who don't want to mess your eyeballs up.

If I were you I would avoid LASIK, Demetrio. IMO, it's really not safe for someone with corneas like yours. The analyses provided by Dr. Shroff and Glenn Hagele are accurate, but neither mentioned the known fact that there is a significant correlation between thin corneas and abnormally weak corneal collagen. Abnormally weak collagen has been implicated in post-LASIK ectasia, even when the residual stromal bed was significantly greater than 250 um, and there was no evidence of FFK, PMD or other corneal disease. With a thin flap you would probably be okay, Demetrio, but why take a chance?

Bryce Carlson