Will Lasik Lead to Corneal Transplant?

The risk of corneal thinning (ectasia) after LASIK is extremely low if the proper precautions are taken and the correct procedure is performed. Even in the few cases where corneal thinning does occur, it's unusual for this to progress to the point where a corneal transplant (PK) is required.

There are several measurements that should be performed to determine your risk of serious corneal problems.  The first is a measure of the corneal thickness using an ultrasound pachymeter.  A healthy cornea that is thick enough to maintain its stability will avoid the problems that you mentioned.  Second is a corneal topography, preferably a device that can measure both the anterior and posterior corneal surfaces.  A normal topography would help rule out keratoconus or potential corneal irregularities.  Third is a history of refractive changes.  A person with a stable glasses prescription that has not changed significantly within the last year would provide confidence that the cornea is not undergoing any change in its integrity.  The large majority of LASIK cases that have led to corneal ectasia could probably have been avoided with these precautions. 

While any type of surgery can result in complications, laser vision correction is among the safest procedures available with very low incidences of complications, particularly among trained corneal specialists.  If you are highly risk averse, LASIK may not be the right choice for you.  Most likely, however, there are other choices you make each day that carry with them high risks that you are not even aware of.  Driving to work in the morning likely carries with it a much greater risk than having a corneal transplant after having LASIK.

For a given corneal thickness the risk of needing a transplant afterwards is always less after Lasek than after LASIK because more untouched tissue would be left

this is why I can do Lasek on patients who can't safely get LASIK eg those with thin corneas high prescriptions or irregular astigmatism 

LASIK is a surgical procedure and as such has the potential of risks.  The risk of needing a corneal transplant after LASIK is extremely small if appropriate tests are performed and found to be normal preoperatively.  I operated on my own wife nearly twelve years ago and would not have done so if I thought that there was a risk.  None of the patients on whom I have operated have needed corneal transplant with my experience of more than 23,000 procedures.  If you have an abnormal cornea, a competent LASIK surgeon should tell you not to have surgery.  It is the first thing that I evaluate in my patients and it is easy in my mind to tell such patients that they are not good candidates for surgery.