title: Optical surface reconstruction technique through combination of zonal and modal fitting.
abstract: Videokeratometers and Scheimpflug cameras permit accurate estimation of corneal surfaces. From height data it is possible to adjust analytical surfaces that will be later used for aberration calculation. Zernike polynomials are often used as adjusting polynomials, but they have shown to be not precise when describing highly irregular surfaces. We propose a combined zonal and modal method that allows an accurate reconstruction of corneal surfaces from height data, diminishing the influence of smooth areas over irregular zones and vice versa. The surface fitting error is decreased in the considered cases, mainly in the central region, which is more important optically. Therefore, the method can be established as an accurate resampling technique.
authors.affiliation: Universidad de Alicante, Department de Optica Campus de San Vicente del Raspeig, P.O. Box 99, Alicante, 03690 Spain. julian.espinosa@ua.es
authors.forename: Julián
authors.initials: J
authors.lastname: Espinosa
authors.forename: David
authors.initials: D
authors.lastname: Mas
authors.forename: Jorge
authors.initials: J
authors.lastname: Pérez
authors.forename: Carlos
authors.initials: C
authors.lastname: Illueca
mesh_terms: D000465:Algorithms; D019781:Corneal Topography / Q000379:methods*; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity