E-mail: [email protected]A. Ehmer, MSc, M.P. Holzer, MD G.U. Auffarth, MD Dept. of Ophthalmology Ruprecht-Karls-University Heidelberg Chairman: H.E.Völcker, MD The authors have no financial interests in any of the products mentioned. Aspherical ablation profiles in excimer laser treatments International Vision Correction Research Centre
International Vision Correction Research Centre. E-mail: [email protected]. Aspherical ablation profiles in excimer laser treatments. Ehmer, MSc, M.P. Holzer, MD G.U. Auffarth, MD. The authors have no financial interests in any of the products mentioned. - PowerPoint PPT Presentation
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Dept. of OphthalmologyRuprecht-Karls-University Heidelberg
Chairman: H.E.Völcker, MD
The authors have no financial interests in any of the products
mentioned.
Aspherical ablation profiles in excimer laser treatments
International Vision Correction Research Centre
Angela Ehmer
Background – Aspheric profile of the cornea
• the curvature of the cornea in the periphery is less compared to the apex Shape of human cornea is no sphere
• Human cornea is comparable to prolate ellipse
• To specify the type of conicoid the parameter Q is used value for asphericity is Q
Variation in conicoid for different asphericities Q, but for the same value of radius R (Source: Kiely et al., 1982)
Q > 0 ellipsoid with the major axis in the X-Y planeQ = 0 sphere-1 < Q < 0 ellipsoid with the major axis in the Z directionQ = -1 paraboloid with the axis along the Z axisQ < -1 hyperboloid
Angela Ehmer
Purpose and Methods
Purpose
• Analysis of corneal shape following excimer laser treatment with an aspheric ablation profile