Mohammed,
You could probably have either LASIK or PRK, but I personally have a bias toward the surface ablation techniques like PRK or its cousin LASEK..
You have a spherical equivalent of a bit less than 3.75 diopters of refractive error and the thinner cornea is 473 microns thick, so lets use these numbers.
If your optical ablation treatment zone is 6.0mm, then you would need about 45 microns of tissue removal to achieve full correction with conventional laser. If you have PRK, your corneal thickness would change from 473 to about 428. That is more than thick enough.
If you were to have LASIK, a flap of corneal tissue is created first. See http://www.usaeyes.org/faq/subjects/lasik.htm This flap provides almost no structural support after surgery, so the important number is the thickness of you untouched cornea under the flap and after the laser tissue removal.
Most LASIK flaps made with a mechanical microkeratome are around 140 microns thick. So we need to start with 473, subtract the 140 micron thick flap, and subtract the 45 microns of tissue removal to come up with 288 microns of untouched tissue. Most doctors agree that 250 microns of untouched tissue in a healthy eye is enough to maintain stability. Based upon these numbers subject to many changes you could have LASIK if you desired.
There are many variables that need to be considered and evaluated. If you have large naturally dilated pupils, you would probably need a larger treatment zone. See http://www.usaeyes.org/faq/subjects/lasik_pupil_size.htm The larger the zone, the greater amount of tissue removal is required per diopter of change. A larger treatment zone would give you a smaller margin for error.
Your doctor could attempt to create a thinner flap, or your LASIK flap could be created with the more precise laser microkeratome (Intralase). See http://www.usaeyes.org/faq/subjects/intralase_intralasik.htm This would give you larger margin for error.
If you elect to have wavefront-guided ablation, more tissue per diopter of refractive change is required. See http://www.usaeyes.org/faq/subjects/wavefront_custom_lasik.htm This would give you a smaller margin for error.
Even though you may be able to have LASIK, it does not mean that you should have LASIK or IntraLASIK.
Several studies have shown that PRK with wavefront-guided ablation provides a superior outcome to LASIK with wavefront-guided ablation.
By eliminating the LASIK flap, you eliminate all possibility of a flap relate complication during surgery or throughout your lifetime. Remember that once you have had LASIK you have always had LASIK and the flap is subject (although very rarely) to problems years after surgery. Eliminating the possibility of complications is a good thing.
PRK and LASEK have a short-term downside. It is less comfortable than LASIK and your vision recovery is not as quick. You would have functional fuzzy vision for 3-5 days and would not get really crisp vision for 2-4 weeks. See http://www.usaeyes.org/faq/subjects/lasek.htm
You need to discuss all these issues with your doctor and determine why in his opinion PRK is better for you. There may be other issues that we have not discussed, or information that we did not consider. You also want to evaluate the quality of your doctor. See http://www.usaeyes.org/faq/tough_questions.htm
Glenn Hagele
http://www.USAEyes.org
I am not a doctor.
