They have no way of knowing if their laser or their technique was consistently shifting the axis clockwise or counterclockwise. They have no way of knowing if their laser was consistently over- or undercorrecting, especially if a shift of axis was occurring. And they have no way of refining their future surgical procedures to correct for all but the grossest surgical errors. And they have no way to determine what they are doing to the corneal topography when they treat solely for refractive astigmatism. Most refractive surgeons do not publish their results, so feel no need to follow patients so closely.
Most refractive surgeons lose a lot of patients to follow-up.
You can find and read these patents using the IBM Patent Server . Alpins' methods also have a number of international patents and patents pending. For a simple graphical explanation, click here . The Coefficient of Adjustment is the inverse of the Correction Index and quantifies the modification needed to the initial surgery plan to have achieved a Correction Index of 1, the ideal correction. The Coefficient of Adjustment can be used to refine future procedures.