Elevation Map

Modesto / Stockton Elevation Map Specialist – Dr. Ash
Serving Tracy, Merced, Manteca Patients

Elevation maps describe the difference in height or elevation of the cornea, in microns, from a reference surface. Placido disc topography systems, like the Humphrey system, can derive elevation data from the corneal surface only when a sophisticated arc step algorithm, magnification, and location and high resolution reflection of the placido rings are used to reconstruct the data. Elevation is different not only in its unit of measurement -- microns -- but also in the way the information is obtained, calculated, and displayed.

When displaying elevation maps, the software will choose which surface will be the "best fit" for a particular eye; this reference model varies from patient to patient. The software then attempts to fit, or superimpose, this model onto the corneal surface, measuring the difference between the model and the real corneal surface.

Elevation can be measured as differences in height from a reference surface as positive or negative microns. The reason for this is that the corneal surface can fall above or below the best fit reference sphere. Positive elevation measurements indicate that the corneal surface is above the reference sphere at that point, while the negative measurement indicate that the corneal surface is below the reference sphere.

In order to deliver the best possible vision correction results for all of his LASIK and cataract surgery Modesto patients, Dr. Amin Ashrafzadeh uses an array of sophisticated vision evaluation technologies. This approach, combined with his advanced surgical skill, allows Dr. Ash to consistently deliver outstanding results for all of his Modesto, Stockton and Tracy LASIK patients.