An Analytically Solvable Model for Biomechanical Response of the Cornea to Refractive Surgery

[+] Author and Article Information
Gagik P. Djotyan

University of Michigan, College of Engineering, Department of Biomedical Engineering, 3304 GG Brown, 2350 Hayward St., Ann Arbor, MI 48109e-mail: jotyan@engin.umich.edu

Ron M. Kurtz

Department of Ophthalmology, University of California, Irvine, Irvine, CAKellogg Eye Center, Department of Ophthalmology, University of Michigan, 1000 Wall Street, Ann Arbor, MI 48105e-mail: rkurtz@uci.edu

Delia Cabrera Fernández

Department of Applied Physics, University of Michigan, 2477 Randall Lab., Ann Arbor, MI 48109-1120e-mail: fcabrera@umich.edu

Tibor Juhasz

University of Michigan, College of Engineering, Department of Biomedical Engineering, 3304 GG Brown, 2350 Hayward St., Ann Arbor, MI 48109Department of Ophthalmology, University of Michigan, 1000 Wall Street, Ann Arbor, MI 48105e-mail: juhasz@umich.edu

J Biomech Eng 123(5), 440-445 (Apr 25, 2001) (6 pages) doi:10.1115/1.1388293 History: Received January 23, 2000; Revised April 25, 2001
Copyright © 2001 by ASME
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Grahic Jump Location
Schematic representation of the cornea and of the treatment zone (for myopic correction)
Grahic Jump Location
Maximum lenticle thickness necessary to correct corneal refractive errors using different values of its diameter: d0=4, 5, 6 (mm). The Young’s modulus E=107 dynes/cw2 and the intraocular pressure p=2 104 dynes/cw2.
Grahic Jump Location
The “best fit” of the predictions based on the elastic shell model with Bausch & Lomb and VISX commercially available nomogram. The fitting parameter is the elasticity parameter Ef: (a) for diameter of the lenticle d0=5 mm; (b) for diameter of the lenticle d0=5.5 mm.
Grahic Jump Location
The nomograms from commercially available Bausch & Lomb software along with the results of calculations based on the elastic shell model for different diameters of removed tissue
Grahic Jump Location
Dependence of the post-operative Young’s modulus of the cornea on the thickness of the removed tissue for different diameters of it
Grahic Jump Location
Comparison of predicted corrections of the elastic shell model with the ALK nomograms. The diameters of the treatment zone are d0=4 mm and 4.2 mm. The value of the Young’s modulus is calculated from Eq. (5) using Table 1.
Grahic Jump Location
Geometry of the corneal refractive surgery for myopia



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