ENG  Vol.5 No.10 B , October 2013
The 3D Computer Image of the Anterior Corneal Surface
Abstract

In this paper,we derive a nonlinearequation of corneal asphericity (Q) usingthe tangential radius of curvature (rt) on every semi-meridian. We transform the nonlinear equation into the linear equation and then obtain theQ-value of cor-neal semi-meridianby the linear regression method.We find the 360 semi-meridional variation rule of theQ-value us-ing polynomial function. Furthermore, we construct a new 3D corneal model and present a more realistic model of shape of the anterior corneal surface.


Cite this paper
Wang, B. , Huang, X. , Ying, J. and Shi, M. (2013) The 3D Computer Image of the Anterior Corneal Surface. Engineering, 5, 477-481. doi: 10.4236/eng.2013.510B098.
References

[1]   K. Scholz, A. Messner, T. Eppig, H. Bruenner and A. Langenbucher, “Topography-Based Assessment of Anterior Corneal Curvature and Asphericity as a Function of Age, Sex, and Refractive Status,” Journal of Cataract & Refractive Surgery, Vol. 35, 2009, pp. 1046-1054. http://dx.doi.org/10.1016/j.jcrs.2009.01.019

[2]   M. Guillon, D. P. M. Lydon and C. Wilson, “Corneal Topography: A Clinical Model,” Ophthalmic and Physiological Optics, Vol. 6, 1986, pp. 47-56. http://dx.doi.org/10.1111/j.1475-1313.1986.tb00699.x

[3]   A. G. Bennett, “Aspherical and Continuous Curve Contact Lenses,” Optometry Today, Vol. 28 ,1988, pp. 11-14, 140-142, 238-242, 433-444.

[4]   T. Y. Baker, “Ray Tracing through Non-Spherical Surfaces,” Proceedings of the Physical Society, Vol. 55, 1943, pp. 361-364. http://dx.doi.org/10.1088/0959-5309/55/5/302

[5]   S. W. Cheung, P. Cho and W. A. Douthwaite, “Corneal Shape of Hong Kong-Chinese,” Ophthalmic and Physiological Optics, Vol. 2, 2000, pp. 119-125. http://dx.doi.org/10.1016/S0275-5408(99)00045-9

[6]   A. G. Bennett and R. B. Rabbetts, “What Radius Does the Conventional Keratometer Measure?” Ophthalmic and Physiological Optics, Vol. 11, 1991, pp. 239-247. http://dx.doi.org/10.1111/j.1475-1313.1991.tb00539.x

[7]   J. Schwiegerling and J. E. Greivenkamp, “Using Corneal Height Maps and Polynomial Decomposition to Determine Corneal Aberrations,” Optometry and Vision Science Journal, Vol. 74, 1997, pp. 906-916. http://dx.doi.org/10.1097/00006324-199711000-00024

[8]   M. Dubbelman, V. A. D. P. Sicam and G. L. Van der Heijde, “The Shape of the Anterior and Posterior Surface of the Aging Human Cornea,” Vision Research, Vol. 46, 2006, pp. 993-1001. http://dx.doi.org/10.1016/j.visres.2005.09.021

[9]   C. Roberts, “Characterization of the Inherent Error in a Spherically-Biased Corneal Topography System in Mapping a Radially Aspheric Surface,” Journal of Cataract & Refractive Surgery, Vol. 10, 1994, pp. 103-111.

[10]   C. Roberts, “Analysis of the Inherent Error of the TMS-1 Topographic Modeling System in Mapping a Radially Aspheric Surface,” Cornea, Vol. 14, 1995, pp. 258-265. http://dx.doi.org/10.1097/00003226-199505000-00006

[11]   J. S. Chan, R. B. Mandell, D. S. Burger and R. E. Fusaro, “Accuracy of Videokeratography for Instantaneous Radius in Keratoconus,” Optometry and Vision Science Journal, Vol. 72, No. 11, 1995, pp. 793-799. http://dx.doi.org/10.1097/00006324-199511000-00004

[12]   L. B. Szczotka and J. Thomas, “Comparison of Axial and Instantaneous Videokeratographic Data in Keratoconus and Utility in Contact Lens Curvature Prediction,” The CLAO Journal, Vol. 24, 1998, pp. 22-28.

[13]   R. B. Mandell, C. S. Chiang and S. A. Klein, “Location of the Major Corneal Reference Points,” Optometry and Vision Science Journal, Vol. 72, 1995, pp. 776-784. http://dx.doi.org/10.1097/00006324-199511000-00002

[14]   A. Gray, “Modern Differential Geometry of Curves and Surfaces with Mathematica,” 2nd Edition, CRC Press, Boca Raton, 1997.

[15]   E. Kreyszig, “Differential Geometry,” Dover, New York, 1991.

[16]   J. D. Foley, A. V. Dam, S. K. Feiner and J. F. Hughes, “Computer Graphics: Principles and Practice in C,” 2nd Edition, Addison-Wesley, Boston, 1995.

[17]   P. M. Kiely, G. Smith and L. G. Carney, “The Mean Shape of the Human Cornea,” Optica Acta, Vol. 29, 1982, pp. 1027-1040. http://dx.doi.org/10.1080/713820960

 
 
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