OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 18, Iss. 18 — Aug. 30, 2010
  • pp: 19324–19338

Forward ray tracing for image projection prediction and surface reconstruction in the evaluation of corneal topography systems

Joris J. Snellenburg, Boy Braaf, Erik A. Hermans, Rob G.L. van der Heijde, and Victor Arni D. P. Sicam  »View Author Affiliations

Optics Express, Vol. 18, Issue 18, pp. 19324-19338 (2010)

View Full Text Article

Enhanced HTML    Acrobat PDF (1253 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



A forward ray tracing (FRT) model is presented to determine the exact image projection in a general corneal topography system. Consequently, the skew ray error in Placido-based topography is demonstrated. A quantitative analysis comparing FRT-based algorithms and Placido-based algorithms in reconstructing the front surface of the cornea shows that arc step algorithms are more sensitive to noise (imprecise). Furthermore, they are less accurate in determining corneal aberrations particularly the quadrafoil aberration. On the other hand, FRT-based algorithms are more accurate and more precise showing that point to point corneal topography is superior compared to its Placido-based counterpart.

© 2010 OSA

ToC Category:
Vision, Color, and Visual Optics

Original Manuscript: July 6, 2010
Revised Manuscript: July 23, 2010
Manuscript Accepted: July 28, 2010
Published: August 26, 2010

Virtual Issues
Vol. 5, Iss. 13 Virtual Journal for Biomedical Optics

Joris J. Snellenburg, Boy Braaf, Erik A. Hermans, Rob G. L. van der Heijde, and Victor Arni D. P. Sicam, "Forward ray tracing for image projection prediction and surface reconstruction in the evaluation of corneal topography systems," Opt. Express 18, 19324-19338 (2010)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. J. Amanatides, “Ray tracing with cones,” Comput. Graph. 18(3), 129–135 (1984). [CrossRef]
  2. C. Bauer, “Direct illuminance caching: a way to enhance the performance of RADIANCE,” Lighting Res. Tech. 34(4), 333–345 (2002). [CrossRef]
  3. V. A. Sicam, J. J. Snellenburg, R. G. van der Heijde, and I. H. van Stokkum, “Pseudo forward ray-tracing: a new method for surface validation in cornea topography,” Optom. Vis. Sci. 84(9), 915–923 (2007). [CrossRef] [PubMed]
  4. J. D. Doss, R. L. Hutson, J. J. Rowsey, and D. R. Brown, “Method for calculation of corneal profile and power distribution,” Arch. Ophthalmol. 99(7), 1261–1265 (1981). [PubMed]
  5. J. Y. Wang, D. A. Rice, and S. D. Klyce, “A new reconstruction algorithm for improvement of corneal topographical analysis,” Refract. Corneal Surg. 5(6), 379–387 (1989). [PubMed]
  6. S. A. Klein, “A corneal topography algorithm that produces continuous curvature,” Optom. Vis. Sci. 69(11), 829–834 (1992). [CrossRef] [PubMed]
  7. R. Mattioli and N. K. Tripoli, “Corneal geometry reconstruction with the Keratron videokeratographer,” Optom. Vis. Sci. 74(11), 881–894 (1997). [CrossRef] [PubMed]
  8. J. Turuwhenua, “An improved low order method for corneal reconstruction,” Optom. Vis. Sci. 85(3), 211–217 (2008). [CrossRef] [PubMed]
  9. N. K. Tripoli, K. L. Cohen, P. Obla, J. M. Coggins, and D. E. Holmgren, “Height measurement of astigmatic test surfaces by a keratoscope that uses plane geometry surface reconstruction,” Am. J. Ophthalmol. 121(6), 668–676 (1996). [PubMed]
  10. S. A. Klein, “Axial curvature and the skew ray error in corneal topography,” Optom. Vis. Sci. 74(11), 931–944 (1997). [CrossRef] [PubMed]
  11. S. A. Klein, “Corneal topography reconstruction algorithm that avoids the skew ray ambiguity and the skew ray error,” Optom. Vis. Sci. 74(11), 945–962 (1997). [CrossRef] [PubMed]
  12. F. M. Vos, R. G. L. van der Heijde, H. J. W. Spoelder, I. H. M. van Stokkum, and F. C. A. Groen, “A New Instrument to Measure the Shape of the Cornea Based on Pseudorandom Color Coding,” IEEE Trans. Instrum. Meas. 46(4), 794–797 (1997). [CrossRef]
  13. T. Swartz, L. Marten, and M. Wang, “Measuring the cornea: the latest developments in corneal topography,” Curr. Opin. Ophthalmol. 18(4), 325–333 (2007). [CrossRef] [PubMed]
  14. J. H. Massig, E. Lingelbach, and B. Lingelbach, “Videokeratoscope for accurate and detailed measurement of the cornea surface,” Appl. Opt. 44(12), 2281–2287 (2005). [CrossRef] [PubMed]
  15. Y. Mejía and J. C. Galeano, “Corneal topographer based on the Hartmann test,” Optom. Vis. Sci. 86(4), 370–381 (2009). [CrossRef] [PubMed]
  16. M. A. Halstead, B. A. Barsky, S. A. Klein, and R. B. Mandell, “A spline surface algorithm for reconstruction of corneal topography from a videokeratographic reflection pattern,” Optom. Vis. Sci. 72(11), 821–827 (1995). [CrossRef] [PubMed]
  17. V. A. Sicam, J. Coppens, T. J. van den Berg, and R. G. van der Heijde, “Corneal surface reconstruction algorithm that uses Zernike polynomial representation,” J. Opt. Soc. Am. A 21(7), 1300–1306 (2004). [CrossRef]
  18. J. Turuwhenua, “Corneal surface reconstruction algorithm using Zernike polynomial representation: improvements,” J. Opt. Soc. Am. A 24(6), 1551–1561 (2007). [CrossRef]
  19. V. A. Sicam and R. G. VAN der Heijde, “Topographer reconstruction of the nonrotation-symmetric anterior corneal surface features,” Optom. Vis. Sci. 83(12), 910–918 (2006). [CrossRef] [PubMed]
  20. V. Sokurenko and V. Molebny, “Damped least-squares approach for point-source corneal topography,” Ophthalmic Physiol. Opt. 29(3), 330–337 (2009). [CrossRef] [PubMed]
  21. L. A. Carvalho, “Accuracy of Zernike polynomials in characterizing optical aberrations and the corneal surface of the eye,” Invest. Ophthalmol. Vis. Sci. 46(6), 1915–1926 (2005). [CrossRef] [PubMed]
  22. Matlab, The Mathworks, Massachusetts, USA.
  23. R. H. Rand, H. C. Howland, and R. A. Applegate, “Mathematical model of a Placido disk keratometer and its implications for recovery of corneal topography,” Optom. Vis. Sci. 74(11), 926–930 (1997). [CrossRef] [PubMed]
  24. S. Marcos, P. Rosales, L. Llorente, and I. Jiménez-Alfaro, “Change in corneal aberrations after cataract surgery with 2 types of aspherical intraocular lenses,” J. Cataract Refract. Surg. 33(2), 217–226 (2007). [CrossRef] [PubMed]
  25. O. Muftuoglu, P. Prasher, R. W. Bowman, J. P. McCulley, and V. V. Mootha, “Corneal higher-order aberrations after Descemet’s stripping automated endothelial keratoplasty,” Ophthalmology 117(5), 878–884, e6 (2010). [CrossRef] [PubMed]
  26. L. N. Thibos, X. Hong, A. Bradley, and X. Cheng, “Statistical variation of aberration structure and image quality in a normal population of healthy eyes,” J. Opt. Soc. Am. A 19(12), 2329–2348 (2002). [CrossRef]
  27. L. A. Carvalho, M. Stefani, A. C. Romão, L. Carvalho, J. C. de Castro, S. Tonissi, P. Schor, and W. Chamon, “Videokeratoscopes for dioptric power measurement during surgery,” J. Cataract Refract. Surg. 28(11), 2006–2016 (2002). [CrossRef] [PubMed]
  28. F. Lu, J. X. Wu, J. Qu, and ., “Association between offset of the pupil center from the corneal vertex and wavefront aberration,” J. Opt. 1, 8–13 (2008).
  29. T. O. Salmon and L. N. Thibos, “Videokeratoscope-line-of-sight misalignment and its effect on measurements of corneal and internal ocular aberrations,” J. Opt. Soc. Am. A 19(4), 657–669 (2002). [CrossRef]
  30. R. A. Applegate, J. D. Marsack, and L. N. Thibos, “Metrics of retinal image quality predict visual performance in eyes with 20/17 or better visual acuity,” Optom. Vis. Sci. 83(9), 635–640 (2006). [CrossRef] [PubMed]
  31. B. Braaf, M. Dubbelman, R. G. van der Heijde, and V. A. Sicam, “Performance in specular reflection and slit-imaging corneal topography,” Optom. Vis. Sci. 86(5), 467–475 (2009). [CrossRef] [PubMed]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited