The danger of acquiring ectasia, or thining of the cornea, after undergoing LASIK is a constant concern for all refractive surgeons. Avoiding this very serious complication is best accomplished by better preoperative testing and weeding out those patients at significant risk. Research has concluded that the best way to evaluate these individuals is to accurately measure the elevation data from the posterior surface of the cornea.

Previously, doctors have attempted to evaluate presurgical patients simply be looking at the anterior surface of the cornea; since that is the easiest location to discover Keratoconus and corneal thinning to some degree. However, true readings must include both anterior(front) and posterior(back) surfaces for accurate thickness measurement. Pachometry (corneal thickness) measurements are the easiest and most sensitive way to get an early reading on potential disasters.

Elevation readings measure both the anterior and posterior surfaces of the cornea which are then displayed in a color map showing differences in the two surfaces using color and numerical schemes. In most, if not all Keratoconus and ectasia patients the early changes in the posterior surface are much more noticeable then the anterior surface.

Unfortunately, some of the early signs of ectasia may be mistaken as signs of contact lens warpage and not corneal pathology. Prior to undergoing any refractive procedure it is imperative to be fully evaluated and the cornea must be with out any irregularities. One must be 100% sure that there are no signs of Keratoconus or ectasia because once the procedure is performed there is no turning back.