LASIK is a refractive surgical procedure that reduces or eliminates the need for eye glasses or contact lenses. It involves creating a flap with either a lathe or laser, called Intralase, and reshaping the underlying tissue. This new corneal curve focuses light on to the retina making it easier to see clearly. Certain conditions make having this procedure unsafe and risk severe post surgical complications. Any corneal condition that affects the water content and hydration of the cornea should be carefully evaluated prior to having LASIK. Failure to do so may result in a hazy or opaque cornea, loss of vision and the need for a corneal transplant post surgically.

On such condition is Posterior Polymorphous Dystrophy (PPMD). Most patients with PPMD never have any symptoms, and are rarely ever diagnosed with the disorder. It is an autosomal-dominant condition with no predilection for sex, race or any other societal selection. The condition does cause corneal swelling, and may also be a sign for glaucoma. This condition also results in a decreased endothelial (bottom layer of the cornea) cell count which will further increase corneal swelling. The endothelium pumps water out of the cornea, and fewer cells results in a weaker pump increasing the water in the corneal tissue.

Other conditions which contraindicate LASIK are a thin cornea usually less the 500 microns. A testing procedure known as Pachymetry must always be done to determine the exact corneal thickness. Orbscans must also always be performed to determine the difference in corneal thickness, and topography between the fronts and back corneal surfaces. Irregularities in this measurement may result in corneal ectasia, which is a warpage of the cornea causing permanent decreased vision. If hard contact lenses do not improve the vision to a satisfactory level then only a corneal transplant will improve the quality of the acuity.

Other contraindications include Fuch's Dystrophy and Pseudophakic Bullous Keratopathy. These conditions also result in a decreased endothelial cell count. In short, any condition that results in a diminished endothelial cell measurement should eliminate LASIK as a procedure of choice. The long term likelihood of complications and corneal edema are far too great. Some of these individuals are candidates for PRK, but much care must be taken to ensure that the endothelium can still support the cornea following this surgery as well.