Abstract

Segmentation of anatomical structures in corneal images is crucial for the diagnosis and study of anterior segment diseases. However, manual segmentation is a time-consuming and subjective process. This paper presents an automatic approach for segmenting corneal layer boundaries in Spectral Domain Optical Coherence Tomography images using graph theory and dynamic programming. Our approach is robust to the low-SNR and different artifact types that can appear in clinical corneal images. We show that our method segments three corneal layer boundaries in normal adult eyes more accurately compared to an expert grader than a second grader—even in the presence of significant imaging outliers.

© 2011 OSA

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  1. D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
    [CrossRef] [PubMed]
  2. J. G. Fujimoto, W. Drexler, J. S. Schuman, and C. K. Hitzenberger, “Optical Coherence Tomography (OCT) in ophthalmology: introduction,” Opt. Express 17(5), 3978–3979 (2009).
    [CrossRef] [PubMed]
  3. J. A. Izatt, M. R. Hee, E. A. Swanson, C. P. Lin, D. Huang, J. S. Schuman, C. A. Puliafito, and J. G. Fujimoto, “Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography,” Arch. Ophthalmol. 112(12), 1584–1589 (1994).
    [PubMed]
  4. S. Radhakrishnan, A. M. Rollins, J. E. Roth, S. Yazdanfar, V. Westphal, D. S. Bardenstein, and J. A. Izatt, “Real-time optical coherence tomography of the anterior segment at 1310 nm,” Arch. Ophthalmol. 119(8), 1179–1185 (2001).
    [PubMed]
  5. Y. Morad, E. Sharon, L. Hefetz, and P. Nemet, “Corneal thickness and curvature in normal-tension glaucoma,” Am. J. Ophthalmol. 125(2), 164–168 (1998).
    [CrossRef] [PubMed]
  6. Z. Liu and S. C. Pflugfelder, “The effects of long-term contact lens wear on corneal thickness, curvature, and surface regularity,” Ophthalmology 107(1), 105–111 (2000).
    [CrossRef] [PubMed]
  7. Z. Liu, A. J. Huang, and S. C. Pflugfelder, “Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system,” Br. J. Ophthalmol. 83(7), 774–778 (1999).
    [CrossRef] [PubMed]
  8. L. J. Müller, E. Pels, and G. F. J. M. Vrensen, “The specific architecture of the anterior stroma accounts for maintenance of corneal curvature,” Br. J. Ophthalmol. 85(4), 437–443 (2001).
    [CrossRef] [PubMed]
  9. B. Seitz, F. Torres, A. Langenbucher, A. Behrens, and E. Suárez, “Posterior corneal curvature changes after myopic laser in situ keratomileusis,” Ophthalmology 108(4), 666–672, discussion 673 (2001).
    [CrossRef] [PubMed]
  10. M. Shimmyo, A. J. Ross, A. Moy, and R. Mostafavi, “Intraocular pressure, Goldmann applanation tension, corneal thickness, and corneal curvature in Caucasians, Asians, Hispanics, and African Americans,” Am. J. Ophthalmol. 136(4), 603–613 (2003).
    [CrossRef] [PubMed]
  11. M. Kohlhaas, A. G. Boehm, E. Spoerl, A. Pürsten, H. J. Grein, and L. E. Pillunat, “Effect of central corneal thickness, corneal curvature, and axial length on applanation tonometry,” Arch. Ophthalmol. 124(4), 471–476 (2006).
    [CrossRef] [PubMed]
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    [CrossRef]
  13. Y. Li, R. Shekhar, and D. Huang, “Corneal pachymetry mapping with high-speed optical coherence tomography,” Ophthalmology 113(5), 792–799.e2 (2006).
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  14. Y. Li, M. V. Netto, R. Shekhar, R. R. Krueger, and D. Huang, “A longitudinal study of LASIK flap and stromal thickness with high-speed optical coherence tomography,” Ophthalmology 114(6), 1124–1132e1 (2007).
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    [CrossRef] [PubMed]
  19. K. Lee, M. Niemeijer, M. K. Garvin, Y. H. Kwon, M. Sonka, and M. D. Abramoff, “Segmentation of the optic disc in 3-D OCT scans of the optic nerve head,” IEEE Trans. Med. Imaging 29(1), 159–168 (2010).
    [CrossRef] [PubMed]
  20. D. A. Tolliver, I. Koutis, H. Ishikawa, J. S. Schuman, and G. L. Miller, “Automatic multiple retinal layer segmentation in spectral domain OCT scans via spectral rounding,” Invest. Ophthalmol. Vis. Sci. 49, 1878-2222 (2008).
  21. S. J. Chiu, X. T. Li, P. Nicholas, C. A. Toth, J. A. Izatt, and S. Farsiu, “Automatic segmentation of seven retinal layers in SDOCT images congruent with expert manual segmentation,” Opt. Express 18(18), 19413–19428 (2010).
    [CrossRef] [PubMed]
  22. M. Zhao, A. N. Kuo, and J. A. Izatt, “3D refraction correction and extraction of clinical parameters from spectral domain optical coherence tomography of the cornea,” Opt. Express 18(9), 8923–8936 (2010).
    [CrossRef] [PubMed]
  23. E. W. Dijkstra, “A note on two problems in connexion with graphs,” Numer. Math. 1(1), 269–271 (1959).
    [CrossRef]
  24. R. Szeliski, “Image alignment and stitching: a tutorial,” Found. Trends Comput. Graphics Vision 2(1), 1–104 (2006).
    [CrossRef]
  25. L. W. Herndon, S. A. Choudhri, T. Cox, K. F. Damji, M. B. Shields, and R. R. Allingham, “Central corneal thickness in normal, glaucomatous, and ocular hypertensive eyes,” Arch. Ophthalmol. 115(9), 1137–1141 (1997).
    [PubMed]
  26. H. F. Li, W. M. Petroll, T. Møller-Pedersen, J. K. Maurer, H. D. Cavanagh, and J. V. Jester, “Epithelial and corneal thickness measurements by in vivo confocal microscopy through focusing (CMTF),” Curr. Eye Res. 16(3), 214–221 (1997).
    [CrossRef] [PubMed]
  27. D. Z. Reinstein, R. H. Silverman, M. J. Rondeau, and D. J. Coleman, “Epithelial and corneal thickness measurements by high-frequency ultrasound digital signal processing,” Ophthalmology 101(1), 140–146 (1994).
    [PubMed]
  28. S. G. Schuman, A. F. Koreishi, S. Farsiu, S. H. Jung, J. A. Izatt, and C. A. Toth, “Photoreceptor layer thinning over drusen in eyes with age-related macular degeneration imaged in vivo with spectral-domain optical coherence tomography,” Ophthalmology 116(3), 488–496e2 (2009).
    [CrossRef] [PubMed]
  29. D. Z. Reinstein, T. J. Archer, M. Gobbe, R. H. Silverman, and D. J. Coleman, “Epithelial thickness in the normal cornea: three-dimensional display with Artemis very high-frequency digital ultrasound,” J. Refract. Surg. 24(6), 571–581 (2008).
    [PubMed]

2010 (4)

N. Hutchings, T. L. Simpson, C. Hyun, A. A. Moayed, S. Hariri, L. Sorbara, and K. Bizheva, “Swelling of the human cornea revealed by high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 51(9), 4579–4584 (2010).
[CrossRef] [PubMed]

K. Lee, M. Niemeijer, M. K. Garvin, Y. H. Kwon, M. Sonka, and M. D. Abramoff, “Segmentation of the optic disc in 3-D OCT scans of the optic nerve head,” IEEE Trans. Med. Imaging 29(1), 159–168 (2010).
[CrossRef] [PubMed]

S. J. Chiu, X. T. Li, P. Nicholas, C. A. Toth, J. A. Izatt, and S. Farsiu, “Automatic segmentation of seven retinal layers in SDOCT images congruent with expert manual segmentation,” Opt. Express 18(18), 19413–19428 (2010).
[CrossRef] [PubMed]

M. Zhao, A. N. Kuo, and J. A. Izatt, “3D refraction correction and extraction of clinical parameters from spectral domain optical coherence tomography of the cornea,” Opt. Express 18(9), 8923–8936 (2010).
[CrossRef] [PubMed]

2009 (3)

S. G. Schuman, A. F. Koreishi, S. Farsiu, S. H. Jung, J. A. Izatt, and C. A. Toth, “Photoreceptor layer thinning over drusen in eyes with age-related macular degeneration imaged in vivo with spectral-domain optical coherence tomography,” Ophthalmology 116(3), 488–496e2 (2009).
[CrossRef] [PubMed]

M. K. Garvin, M. D. Abràmoff, X. Wu, S. R. Russell, T. L. Burns, and M. Sonka, “Automated 3-D intraretinal layer segmentation of macular spectral-domain optical coherence tomography images,” IEEE Trans. Med. Imaging 28(9), 1436–1447 (2009).
[CrossRef] [PubMed]

J. G. Fujimoto, W. Drexler, J. S. Schuman, and C. K. Hitzenberger, “Optical Coherence Tomography (OCT) in ophthalmology: introduction,” Opt. Express 17(5), 3978–3979 (2009).
[CrossRef] [PubMed]

2008 (2)

D. Z. Reinstein, T. J. Archer, M. Gobbe, R. H. Silverman, and D. J. Coleman, “Epithelial thickness in the normal cornea: three-dimensional display with Artemis very high-frequency digital ultrasound,” J. Refract. Surg. 24(6), 571–581 (2008).
[PubMed]

D. A. Tolliver, I. Koutis, H. Ishikawa, J. S. Schuman, and G. L. Miller, “Automatic multiple retinal layer segmentation in spectral domain OCT scans via spectral rounding,” Invest. Ophthalmol. Vis. Sci. 49, 1878-2222 (2008).

2007 (2)

M. Haeker, M. Sonka, R. Kardon, V. A. Shah, X. Wu, and M. D. Abramoff, “Automated segmentation of intraretinal layers from macular optical coherence tomography images,” Proc. SPIE 6512, 651214 (2007).
[CrossRef]

Y. Li, M. V. Netto, R. Shekhar, R. R. Krueger, and D. Huang, “A longitudinal study of LASIK flap and stromal thickness with high-speed optical coherence tomography,” Ophthalmology 114(6), 1124–1132e1 (2007).
[CrossRef] [PubMed]

2006 (3)

Y. Li, R. Shekhar, and D. Huang, “Corneal pachymetry mapping with high-speed optical coherence tomography,” Ophthalmology 113(5), 792–799.e2 (2006).
[CrossRef] [PubMed]

M. Kohlhaas, A. G. Boehm, E. Spoerl, A. Pürsten, H. J. Grein, and L. E. Pillunat, “Effect of central corneal thickness, corneal curvature, and axial length on applanation tonometry,” Arch. Ophthalmol. 124(4), 471–476 (2006).
[CrossRef] [PubMed]

R. Szeliski, “Image alignment and stitching: a tutorial,” Found. Trends Comput. Graphics Vision 2(1), 1–104 (2006).
[CrossRef]

2003 (1)

M. Shimmyo, A. J. Ross, A. Moy, and R. Mostafavi, “Intraocular pressure, Goldmann applanation tension, corneal thickness, and corneal curvature in Caucasians, Asians, Hispanics, and African Americans,” Am. J. Ophthalmol. 136(4), 603–613 (2003).
[CrossRef] [PubMed]

2002 (1)

Y. Li, R. Shekhar, and D. Huang, “Segmentation of 830- and 1310-nm LASIK corneal optical coherence tomography images,” Proc. SPIE 4684, 167–178 (2002).
[CrossRef]

2001 (3)

S. Radhakrishnan, A. M. Rollins, J. E. Roth, S. Yazdanfar, V. Westphal, D. S. Bardenstein, and J. A. Izatt, “Real-time optical coherence tomography of the anterior segment at 1310 nm,” Arch. Ophthalmol. 119(8), 1179–1185 (2001).
[PubMed]

L. J. Müller, E. Pels, and G. F. J. M. Vrensen, “The specific architecture of the anterior stroma accounts for maintenance of corneal curvature,” Br. J. Ophthalmol. 85(4), 437–443 (2001).
[CrossRef] [PubMed]

B. Seitz, F. Torres, A. Langenbucher, A. Behrens, and E. Suárez, “Posterior corneal curvature changes after myopic laser in situ keratomileusis,” Ophthalmology 108(4), 666–672, discussion 673 (2001).
[CrossRef] [PubMed]

2000 (1)

Z. Liu and S. C. Pflugfelder, “The effects of long-term contact lens wear on corneal thickness, curvature, and surface regularity,” Ophthalmology 107(1), 105–111 (2000).
[CrossRef] [PubMed]

1999 (1)

Z. Liu, A. J. Huang, and S. C. Pflugfelder, “Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system,” Br. J. Ophthalmol. 83(7), 774–778 (1999).
[CrossRef] [PubMed]

1998 (1)

Y. Morad, E. Sharon, L. Hefetz, and P. Nemet, “Corneal thickness and curvature in normal-tension glaucoma,” Am. J. Ophthalmol. 125(2), 164–168 (1998).
[CrossRef] [PubMed]

1997 (2)

L. W. Herndon, S. A. Choudhri, T. Cox, K. F. Damji, M. B. Shields, and R. R. Allingham, “Central corneal thickness in normal, glaucomatous, and ocular hypertensive eyes,” Arch. Ophthalmol. 115(9), 1137–1141 (1997).
[PubMed]

H. F. Li, W. M. Petroll, T. Møller-Pedersen, J. K. Maurer, H. D. Cavanagh, and J. V. Jester, “Epithelial and corneal thickness measurements by in vivo confocal microscopy through focusing (CMTF),” Curr. Eye Res. 16(3), 214–221 (1997).
[CrossRef] [PubMed]

1994 (2)

D. Z. Reinstein, R. H. Silverman, M. J. Rondeau, and D. J. Coleman, “Epithelial and corneal thickness measurements by high-frequency ultrasound digital signal processing,” Ophthalmology 101(1), 140–146 (1994).
[PubMed]

J. A. Izatt, M. R. Hee, E. A. Swanson, C. P. Lin, D. Huang, J. S. Schuman, C. A. Puliafito, and J. G. Fujimoto, “Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography,” Arch. Ophthalmol. 112(12), 1584–1589 (1994).
[PubMed]

1991 (1)

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

1959 (1)

E. W. Dijkstra, “A note on two problems in connexion with graphs,” Numer. Math. 1(1), 269–271 (1959).
[CrossRef]

Abramoff, M. D.

K. Lee, M. Niemeijer, M. K. Garvin, Y. H. Kwon, M. Sonka, and M. D. Abramoff, “Segmentation of the optic disc in 3-D OCT scans of the optic nerve head,” IEEE Trans. Med. Imaging 29(1), 159–168 (2010).
[CrossRef] [PubMed]

M. Haeker, M. Sonka, R. Kardon, V. A. Shah, X. Wu, and M. D. Abramoff, “Automated segmentation of intraretinal layers from macular optical coherence tomography images,” Proc. SPIE 6512, 651214 (2007).
[CrossRef]

Abràmoff, M. D.

M. K. Garvin, M. D. Abràmoff, X. Wu, S. R. Russell, T. L. Burns, and M. Sonka, “Automated 3-D intraretinal layer segmentation of macular spectral-domain optical coherence tomography images,” IEEE Trans. Med. Imaging 28(9), 1436–1447 (2009).
[CrossRef] [PubMed]

Allingham, R. R.

L. W. Herndon, S. A. Choudhri, T. Cox, K. F. Damji, M. B. Shields, and R. R. Allingham, “Central corneal thickness in normal, glaucomatous, and ocular hypertensive eyes,” Arch. Ophthalmol. 115(9), 1137–1141 (1997).
[PubMed]

Archer, T. J.

D. Z. Reinstein, T. J. Archer, M. Gobbe, R. H. Silverman, and D. J. Coleman, “Epithelial thickness in the normal cornea: three-dimensional display with Artemis very high-frequency digital ultrasound,” J. Refract. Surg. 24(6), 571–581 (2008).
[PubMed]

Bardenstein, D. S.

S. Radhakrishnan, A. M. Rollins, J. E. Roth, S. Yazdanfar, V. Westphal, D. S. Bardenstein, and J. A. Izatt, “Real-time optical coherence tomography of the anterior segment at 1310 nm,” Arch. Ophthalmol. 119(8), 1179–1185 (2001).
[PubMed]

Behrens, A.

B. Seitz, F. Torres, A. Langenbucher, A. Behrens, and E. Suárez, “Posterior corneal curvature changes after myopic laser in situ keratomileusis,” Ophthalmology 108(4), 666–672, discussion 673 (2001).
[CrossRef] [PubMed]

Bizheva, K.

N. Hutchings, T. L. Simpson, C. Hyun, A. A. Moayed, S. Hariri, L. Sorbara, and K. Bizheva, “Swelling of the human cornea revealed by high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 51(9), 4579–4584 (2010).
[CrossRef] [PubMed]

Boehm, A. G.

M. Kohlhaas, A. G. Boehm, E. Spoerl, A. Pürsten, H. J. Grein, and L. E. Pillunat, “Effect of central corneal thickness, corneal curvature, and axial length on applanation tonometry,” Arch. Ophthalmol. 124(4), 471–476 (2006).
[CrossRef] [PubMed]

Burns, T. L.

M. K. Garvin, M. D. Abràmoff, X. Wu, S. R. Russell, T. L. Burns, and M. Sonka, “Automated 3-D intraretinal layer segmentation of macular spectral-domain optical coherence tomography images,” IEEE Trans. Med. Imaging 28(9), 1436–1447 (2009).
[CrossRef] [PubMed]

Cavanagh, H. D.

H. F. Li, W. M. Petroll, T. Møller-Pedersen, J. K. Maurer, H. D. Cavanagh, and J. V. Jester, “Epithelial and corneal thickness measurements by in vivo confocal microscopy through focusing (CMTF),” Curr. Eye Res. 16(3), 214–221 (1997).
[CrossRef] [PubMed]

Chang, W.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Chiu, S. J.

Choudhri, S. A.

L. W. Herndon, S. A. Choudhri, T. Cox, K. F. Damji, M. B. Shields, and R. R. Allingham, “Central corneal thickness in normal, glaucomatous, and ocular hypertensive eyes,” Arch. Ophthalmol. 115(9), 1137–1141 (1997).
[PubMed]

Coleman, D. J.

D. Z. Reinstein, T. J. Archer, M. Gobbe, R. H. Silverman, and D. J. Coleman, “Epithelial thickness in the normal cornea: three-dimensional display with Artemis very high-frequency digital ultrasound,” J. Refract. Surg. 24(6), 571–581 (2008).
[PubMed]

D. Z. Reinstein, R. H. Silverman, M. J. Rondeau, and D. J. Coleman, “Epithelial and corneal thickness measurements by high-frequency ultrasound digital signal processing,” Ophthalmology 101(1), 140–146 (1994).
[PubMed]

Cox, T.

L. W. Herndon, S. A. Choudhri, T. Cox, K. F. Damji, M. B. Shields, and R. R. Allingham, “Central corneal thickness in normal, glaucomatous, and ocular hypertensive eyes,” Arch. Ophthalmol. 115(9), 1137–1141 (1997).
[PubMed]

Damji, K. F.

L. W. Herndon, S. A. Choudhri, T. Cox, K. F. Damji, M. B. Shields, and R. R. Allingham, “Central corneal thickness in normal, glaucomatous, and ocular hypertensive eyes,” Arch. Ophthalmol. 115(9), 1137–1141 (1997).
[PubMed]

Dijkstra, E. W.

E. W. Dijkstra, “A note on two problems in connexion with graphs,” Numer. Math. 1(1), 269–271 (1959).
[CrossRef]

Drexler, W.

Farsiu, S.

S. J. Chiu, X. T. Li, P. Nicholas, C. A. Toth, J. A. Izatt, and S. Farsiu, “Automatic segmentation of seven retinal layers in SDOCT images congruent with expert manual segmentation,” Opt. Express 18(18), 19413–19428 (2010).
[CrossRef] [PubMed]

S. G. Schuman, A. F. Koreishi, S. Farsiu, S. H. Jung, J. A. Izatt, and C. A. Toth, “Photoreceptor layer thinning over drusen in eyes with age-related macular degeneration imaged in vivo with spectral-domain optical coherence tomography,” Ophthalmology 116(3), 488–496e2 (2009).
[CrossRef] [PubMed]

Flotte, T.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Fujimoto, J. G.

J. G. Fujimoto, W. Drexler, J. S. Schuman, and C. K. Hitzenberger, “Optical Coherence Tomography (OCT) in ophthalmology: introduction,” Opt. Express 17(5), 3978–3979 (2009).
[CrossRef] [PubMed]

J. A. Izatt, M. R. Hee, E. A. Swanson, C. P. Lin, D. Huang, J. S. Schuman, C. A. Puliafito, and J. G. Fujimoto, “Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography,” Arch. Ophthalmol. 112(12), 1584–1589 (1994).
[PubMed]

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Garvin, M. K.

K. Lee, M. Niemeijer, M. K. Garvin, Y. H. Kwon, M. Sonka, and M. D. Abramoff, “Segmentation of the optic disc in 3-D OCT scans of the optic nerve head,” IEEE Trans. Med. Imaging 29(1), 159–168 (2010).
[CrossRef] [PubMed]

M. K. Garvin, M. D. Abràmoff, X. Wu, S. R. Russell, T. L. Burns, and M. Sonka, “Automated 3-D intraretinal layer segmentation of macular spectral-domain optical coherence tomography images,” IEEE Trans. Med. Imaging 28(9), 1436–1447 (2009).
[CrossRef] [PubMed]

Gobbe, M.

D. Z. Reinstein, T. J. Archer, M. Gobbe, R. H. Silverman, and D. J. Coleman, “Epithelial thickness in the normal cornea: three-dimensional display with Artemis very high-frequency digital ultrasound,” J. Refract. Surg. 24(6), 571–581 (2008).
[PubMed]

Gregory, K.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Grein, H. J.

M. Kohlhaas, A. G. Boehm, E. Spoerl, A. Pürsten, H. J. Grein, and L. E. Pillunat, “Effect of central corneal thickness, corneal curvature, and axial length on applanation tonometry,” Arch. Ophthalmol. 124(4), 471–476 (2006).
[CrossRef] [PubMed]

Haeker, M.

M. Haeker, M. Sonka, R. Kardon, V. A. Shah, X. Wu, and M. D. Abramoff, “Automated segmentation of intraretinal layers from macular optical coherence tomography images,” Proc. SPIE 6512, 651214 (2007).
[CrossRef]

Hariri, S.

N. Hutchings, T. L. Simpson, C. Hyun, A. A. Moayed, S. Hariri, L. Sorbara, and K. Bizheva, “Swelling of the human cornea revealed by high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 51(9), 4579–4584 (2010).
[CrossRef] [PubMed]

Hee, M. R.

J. A. Izatt, M. R. Hee, E. A. Swanson, C. P. Lin, D. Huang, J. S. Schuman, C. A. Puliafito, and J. G. Fujimoto, “Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography,” Arch. Ophthalmol. 112(12), 1584–1589 (1994).
[PubMed]

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Hefetz, L.

Y. Morad, E. Sharon, L. Hefetz, and P. Nemet, “Corneal thickness and curvature in normal-tension glaucoma,” Am. J. Ophthalmol. 125(2), 164–168 (1998).
[CrossRef] [PubMed]

Herndon, L. W.

L. W. Herndon, S. A. Choudhri, T. Cox, K. F. Damji, M. B. Shields, and R. R. Allingham, “Central corneal thickness in normal, glaucomatous, and ocular hypertensive eyes,” Arch. Ophthalmol. 115(9), 1137–1141 (1997).
[PubMed]

Hitzenberger, C. K.

Huang, A. J.

Z. Liu, A. J. Huang, and S. C. Pflugfelder, “Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system,” Br. J. Ophthalmol. 83(7), 774–778 (1999).
[CrossRef] [PubMed]

Huang, D.

Y. Li, M. V. Netto, R. Shekhar, R. R. Krueger, and D. Huang, “A longitudinal study of LASIK flap and stromal thickness with high-speed optical coherence tomography,” Ophthalmology 114(6), 1124–1132e1 (2007).
[CrossRef] [PubMed]

Y. Li, R. Shekhar, and D. Huang, “Corneal pachymetry mapping with high-speed optical coherence tomography,” Ophthalmology 113(5), 792–799.e2 (2006).
[CrossRef] [PubMed]

Y. Li, R. Shekhar, and D. Huang, “Segmentation of 830- and 1310-nm LASIK corneal optical coherence tomography images,” Proc. SPIE 4684, 167–178 (2002).
[CrossRef]

J. A. Izatt, M. R. Hee, E. A. Swanson, C. P. Lin, D. Huang, J. S. Schuman, C. A. Puliafito, and J. G. Fujimoto, “Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography,” Arch. Ophthalmol. 112(12), 1584–1589 (1994).
[PubMed]

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Hutchings, N.

N. Hutchings, T. L. Simpson, C. Hyun, A. A. Moayed, S. Hariri, L. Sorbara, and K. Bizheva, “Swelling of the human cornea revealed by high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 51(9), 4579–4584 (2010).
[CrossRef] [PubMed]

Hyun, C.

N. Hutchings, T. L. Simpson, C. Hyun, A. A. Moayed, S. Hariri, L. Sorbara, and K. Bizheva, “Swelling of the human cornea revealed by high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 51(9), 4579–4584 (2010).
[CrossRef] [PubMed]

Ishikawa, H.

D. A. Tolliver, I. Koutis, H. Ishikawa, J. S. Schuman, and G. L. Miller, “Automatic multiple retinal layer segmentation in spectral domain OCT scans via spectral rounding,” Invest. Ophthalmol. Vis. Sci. 49, 1878-2222 (2008).

Izatt, J. A.

S. J. Chiu, X. T. Li, P. Nicholas, C. A. Toth, J. A. Izatt, and S. Farsiu, “Automatic segmentation of seven retinal layers in SDOCT images congruent with expert manual segmentation,” Opt. Express 18(18), 19413–19428 (2010).
[CrossRef] [PubMed]

M. Zhao, A. N. Kuo, and J. A. Izatt, “3D refraction correction and extraction of clinical parameters from spectral domain optical coherence tomography of the cornea,” Opt. Express 18(9), 8923–8936 (2010).
[CrossRef] [PubMed]

S. G. Schuman, A. F. Koreishi, S. Farsiu, S. H. Jung, J. A. Izatt, and C. A. Toth, “Photoreceptor layer thinning over drusen in eyes with age-related macular degeneration imaged in vivo with spectral-domain optical coherence tomography,” Ophthalmology 116(3), 488–496e2 (2009).
[CrossRef] [PubMed]

S. Radhakrishnan, A. M. Rollins, J. E. Roth, S. Yazdanfar, V. Westphal, D. S. Bardenstein, and J. A. Izatt, “Real-time optical coherence tomography of the anterior segment at 1310 nm,” Arch. Ophthalmol. 119(8), 1179–1185 (2001).
[PubMed]

J. A. Izatt, M. R. Hee, E. A. Swanson, C. P. Lin, D. Huang, J. S. Schuman, C. A. Puliafito, and J. G. Fujimoto, “Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography,” Arch. Ophthalmol. 112(12), 1584–1589 (1994).
[PubMed]

Jester, J. V.

H. F. Li, W. M. Petroll, T. Møller-Pedersen, J. K. Maurer, H. D. Cavanagh, and J. V. Jester, “Epithelial and corneal thickness measurements by in vivo confocal microscopy through focusing (CMTF),” Curr. Eye Res. 16(3), 214–221 (1997).
[CrossRef] [PubMed]

Jung, S. H.

S. G. Schuman, A. F. Koreishi, S. Farsiu, S. H. Jung, J. A. Izatt, and C. A. Toth, “Photoreceptor layer thinning over drusen in eyes with age-related macular degeneration imaged in vivo with spectral-domain optical coherence tomography,” Ophthalmology 116(3), 488–496e2 (2009).
[CrossRef] [PubMed]

Kardon, R.

M. Haeker, M. Sonka, R. Kardon, V. A. Shah, X. Wu, and M. D. Abramoff, “Automated segmentation of intraretinal layers from macular optical coherence tomography images,” Proc. SPIE 6512, 651214 (2007).
[CrossRef]

Kohlhaas, M.

M. Kohlhaas, A. G. Boehm, E. Spoerl, A. Pürsten, H. J. Grein, and L. E. Pillunat, “Effect of central corneal thickness, corneal curvature, and axial length on applanation tonometry,” Arch. Ophthalmol. 124(4), 471–476 (2006).
[CrossRef] [PubMed]

Koreishi, A. F.

S. G. Schuman, A. F. Koreishi, S. Farsiu, S. H. Jung, J. A. Izatt, and C. A. Toth, “Photoreceptor layer thinning over drusen in eyes with age-related macular degeneration imaged in vivo with spectral-domain optical coherence tomography,” Ophthalmology 116(3), 488–496e2 (2009).
[CrossRef] [PubMed]

Koutis, I.

D. A. Tolliver, I. Koutis, H. Ishikawa, J. S. Schuman, and G. L. Miller, “Automatic multiple retinal layer segmentation in spectral domain OCT scans via spectral rounding,” Invest. Ophthalmol. Vis. Sci. 49, 1878-2222 (2008).

Krueger, R. R.

Y. Li, M. V. Netto, R. Shekhar, R. R. Krueger, and D. Huang, “A longitudinal study of LASIK flap and stromal thickness with high-speed optical coherence tomography,” Ophthalmology 114(6), 1124–1132e1 (2007).
[CrossRef] [PubMed]

Kuo, A. N.

Kwon, Y. H.

K. Lee, M. Niemeijer, M. K. Garvin, Y. H. Kwon, M. Sonka, and M. D. Abramoff, “Segmentation of the optic disc in 3-D OCT scans of the optic nerve head,” IEEE Trans. Med. Imaging 29(1), 159–168 (2010).
[CrossRef] [PubMed]

Langenbucher, A.

B. Seitz, F. Torres, A. Langenbucher, A. Behrens, and E. Suárez, “Posterior corneal curvature changes after myopic laser in situ keratomileusis,” Ophthalmology 108(4), 666–672, discussion 673 (2001).
[CrossRef] [PubMed]

Lee, K.

K. Lee, M. Niemeijer, M. K. Garvin, Y. H. Kwon, M. Sonka, and M. D. Abramoff, “Segmentation of the optic disc in 3-D OCT scans of the optic nerve head,” IEEE Trans. Med. Imaging 29(1), 159–168 (2010).
[CrossRef] [PubMed]

Li, H. F.

H. F. Li, W. M. Petroll, T. Møller-Pedersen, J. K. Maurer, H. D. Cavanagh, and J. V. Jester, “Epithelial and corneal thickness measurements by in vivo confocal microscopy through focusing (CMTF),” Curr. Eye Res. 16(3), 214–221 (1997).
[CrossRef] [PubMed]

Li, X. T.

Li, Y.

Y. Li, M. V. Netto, R. Shekhar, R. R. Krueger, and D. Huang, “A longitudinal study of LASIK flap and stromal thickness with high-speed optical coherence tomography,” Ophthalmology 114(6), 1124–1132e1 (2007).
[CrossRef] [PubMed]

Y. Li, R. Shekhar, and D. Huang, “Corneal pachymetry mapping with high-speed optical coherence tomography,” Ophthalmology 113(5), 792–799.e2 (2006).
[CrossRef] [PubMed]

Y. Li, R. Shekhar, and D. Huang, “Segmentation of 830- and 1310-nm LASIK corneal optical coherence tomography images,” Proc. SPIE 4684, 167–178 (2002).
[CrossRef]

Lin, C. P.

J. A. Izatt, M. R. Hee, E. A. Swanson, C. P. Lin, D. Huang, J. S. Schuman, C. A. Puliafito, and J. G. Fujimoto, “Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography,” Arch. Ophthalmol. 112(12), 1584–1589 (1994).
[PubMed]

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Liu, Z.

Z. Liu and S. C. Pflugfelder, “The effects of long-term contact lens wear on corneal thickness, curvature, and surface regularity,” Ophthalmology 107(1), 105–111 (2000).
[CrossRef] [PubMed]

Z. Liu, A. J. Huang, and S. C. Pflugfelder, “Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system,” Br. J. Ophthalmol. 83(7), 774–778 (1999).
[CrossRef] [PubMed]

Maurer, J. K.

H. F. Li, W. M. Petroll, T. Møller-Pedersen, J. K. Maurer, H. D. Cavanagh, and J. V. Jester, “Epithelial and corneal thickness measurements by in vivo confocal microscopy through focusing (CMTF),” Curr. Eye Res. 16(3), 214–221 (1997).
[CrossRef] [PubMed]

Miller, G. L.

D. A. Tolliver, I. Koutis, H. Ishikawa, J. S. Schuman, and G. L. Miller, “Automatic multiple retinal layer segmentation in spectral domain OCT scans via spectral rounding,” Invest. Ophthalmol. Vis. Sci. 49, 1878-2222 (2008).

Moayed, A. A.

N. Hutchings, T. L. Simpson, C. Hyun, A. A. Moayed, S. Hariri, L. Sorbara, and K. Bizheva, “Swelling of the human cornea revealed by high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 51(9), 4579–4584 (2010).
[CrossRef] [PubMed]

Møller-Pedersen, T.

H. F. Li, W. M. Petroll, T. Møller-Pedersen, J. K. Maurer, H. D. Cavanagh, and J. V. Jester, “Epithelial and corneal thickness measurements by in vivo confocal microscopy through focusing (CMTF),” Curr. Eye Res. 16(3), 214–221 (1997).
[CrossRef] [PubMed]

Morad, Y.

Y. Morad, E. Sharon, L. Hefetz, and P. Nemet, “Corneal thickness and curvature in normal-tension glaucoma,” Am. J. Ophthalmol. 125(2), 164–168 (1998).
[CrossRef] [PubMed]

Mostafavi, R.

M. Shimmyo, A. J. Ross, A. Moy, and R. Mostafavi, “Intraocular pressure, Goldmann applanation tension, corneal thickness, and corneal curvature in Caucasians, Asians, Hispanics, and African Americans,” Am. J. Ophthalmol. 136(4), 603–613 (2003).
[CrossRef] [PubMed]

Moy, A.

M. Shimmyo, A. J. Ross, A. Moy, and R. Mostafavi, “Intraocular pressure, Goldmann applanation tension, corneal thickness, and corneal curvature in Caucasians, Asians, Hispanics, and African Americans,” Am. J. Ophthalmol. 136(4), 603–613 (2003).
[CrossRef] [PubMed]

Müller, L. J.

L. J. Müller, E. Pels, and G. F. J. M. Vrensen, “The specific architecture of the anterior stroma accounts for maintenance of corneal curvature,” Br. J. Ophthalmol. 85(4), 437–443 (2001).
[CrossRef] [PubMed]

Nemet, P.

Y. Morad, E. Sharon, L. Hefetz, and P. Nemet, “Corneal thickness and curvature in normal-tension glaucoma,” Am. J. Ophthalmol. 125(2), 164–168 (1998).
[CrossRef] [PubMed]

Netto, M. V.

Y. Li, M. V. Netto, R. Shekhar, R. R. Krueger, and D. Huang, “A longitudinal study of LASIK flap and stromal thickness with high-speed optical coherence tomography,” Ophthalmology 114(6), 1124–1132e1 (2007).
[CrossRef] [PubMed]

Nicholas, P.

Niemeijer, M.

K. Lee, M. Niemeijer, M. K. Garvin, Y. H. Kwon, M. Sonka, and M. D. Abramoff, “Segmentation of the optic disc in 3-D OCT scans of the optic nerve head,” IEEE Trans. Med. Imaging 29(1), 159–168 (2010).
[CrossRef] [PubMed]

Pels, E.

L. J. Müller, E. Pels, and G. F. J. M. Vrensen, “The specific architecture of the anterior stroma accounts for maintenance of corneal curvature,” Br. J. Ophthalmol. 85(4), 437–443 (2001).
[CrossRef] [PubMed]

Petroll, W. M.

H. F. Li, W. M. Petroll, T. Møller-Pedersen, J. K. Maurer, H. D. Cavanagh, and J. V. Jester, “Epithelial and corneal thickness measurements by in vivo confocal microscopy through focusing (CMTF),” Curr. Eye Res. 16(3), 214–221 (1997).
[CrossRef] [PubMed]

Pflugfelder, S. C.

Z. Liu and S. C. Pflugfelder, “The effects of long-term contact lens wear on corneal thickness, curvature, and surface regularity,” Ophthalmology 107(1), 105–111 (2000).
[CrossRef] [PubMed]

Z. Liu, A. J. Huang, and S. C. Pflugfelder, “Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system,” Br. J. Ophthalmol. 83(7), 774–778 (1999).
[CrossRef] [PubMed]

Pillunat, L. E.

M. Kohlhaas, A. G. Boehm, E. Spoerl, A. Pürsten, H. J. Grein, and L. E. Pillunat, “Effect of central corneal thickness, corneal curvature, and axial length on applanation tonometry,” Arch. Ophthalmol. 124(4), 471–476 (2006).
[CrossRef] [PubMed]

Puliafito, C. A.

J. A. Izatt, M. R. Hee, E. A. Swanson, C. P. Lin, D. Huang, J. S. Schuman, C. A. Puliafito, and J. G. Fujimoto, “Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography,” Arch. Ophthalmol. 112(12), 1584–1589 (1994).
[PubMed]

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Pürsten, A.

M. Kohlhaas, A. G. Boehm, E. Spoerl, A. Pürsten, H. J. Grein, and L. E. Pillunat, “Effect of central corneal thickness, corneal curvature, and axial length on applanation tonometry,” Arch. Ophthalmol. 124(4), 471–476 (2006).
[CrossRef] [PubMed]

Radhakrishnan, S.

S. Radhakrishnan, A. M. Rollins, J. E. Roth, S. Yazdanfar, V. Westphal, D. S. Bardenstein, and J. A. Izatt, “Real-time optical coherence tomography of the anterior segment at 1310 nm,” Arch. Ophthalmol. 119(8), 1179–1185 (2001).
[PubMed]

Reinstein, D. Z.

D. Z. Reinstein, T. J. Archer, M. Gobbe, R. H. Silverman, and D. J. Coleman, “Epithelial thickness in the normal cornea: three-dimensional display with Artemis very high-frequency digital ultrasound,” J. Refract. Surg. 24(6), 571–581 (2008).
[PubMed]

D. Z. Reinstein, R. H. Silverman, M. J. Rondeau, and D. J. Coleman, “Epithelial and corneal thickness measurements by high-frequency ultrasound digital signal processing,” Ophthalmology 101(1), 140–146 (1994).
[PubMed]

Rollins, A. M.

S. Radhakrishnan, A. M. Rollins, J. E. Roth, S. Yazdanfar, V. Westphal, D. S. Bardenstein, and J. A. Izatt, “Real-time optical coherence tomography of the anterior segment at 1310 nm,” Arch. Ophthalmol. 119(8), 1179–1185 (2001).
[PubMed]

Rondeau, M. J.

D. Z. Reinstein, R. H. Silverman, M. J. Rondeau, and D. J. Coleman, “Epithelial and corneal thickness measurements by high-frequency ultrasound digital signal processing,” Ophthalmology 101(1), 140–146 (1994).
[PubMed]

Ross, A. J.

M. Shimmyo, A. J. Ross, A. Moy, and R. Mostafavi, “Intraocular pressure, Goldmann applanation tension, corneal thickness, and corneal curvature in Caucasians, Asians, Hispanics, and African Americans,” Am. J. Ophthalmol. 136(4), 603–613 (2003).
[CrossRef] [PubMed]

Roth, J. E.

S. Radhakrishnan, A. M. Rollins, J. E. Roth, S. Yazdanfar, V. Westphal, D. S. Bardenstein, and J. A. Izatt, “Real-time optical coherence tomography of the anterior segment at 1310 nm,” Arch. Ophthalmol. 119(8), 1179–1185 (2001).
[PubMed]

Russell, S. R.

M. K. Garvin, M. D. Abràmoff, X. Wu, S. R. Russell, T. L. Burns, and M. Sonka, “Automated 3-D intraretinal layer segmentation of macular spectral-domain optical coherence tomography images,” IEEE Trans. Med. Imaging 28(9), 1436–1447 (2009).
[CrossRef] [PubMed]

Schuman, J. S.

J. G. Fujimoto, W. Drexler, J. S. Schuman, and C. K. Hitzenberger, “Optical Coherence Tomography (OCT) in ophthalmology: introduction,” Opt. Express 17(5), 3978–3979 (2009).
[CrossRef] [PubMed]

D. A. Tolliver, I. Koutis, H. Ishikawa, J. S. Schuman, and G. L. Miller, “Automatic multiple retinal layer segmentation in spectral domain OCT scans via spectral rounding,” Invest. Ophthalmol. Vis. Sci. 49, 1878-2222 (2008).

J. A. Izatt, M. R. Hee, E. A. Swanson, C. P. Lin, D. Huang, J. S. Schuman, C. A. Puliafito, and J. G. Fujimoto, “Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography,” Arch. Ophthalmol. 112(12), 1584–1589 (1994).
[PubMed]

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Schuman, S. G.

S. G. Schuman, A. F. Koreishi, S. Farsiu, S. H. Jung, J. A. Izatt, and C. A. Toth, “Photoreceptor layer thinning over drusen in eyes with age-related macular degeneration imaged in vivo with spectral-domain optical coherence tomography,” Ophthalmology 116(3), 488–496e2 (2009).
[CrossRef] [PubMed]

Seitz, B.

B. Seitz, F. Torres, A. Langenbucher, A. Behrens, and E. Suárez, “Posterior corneal curvature changes after myopic laser in situ keratomileusis,” Ophthalmology 108(4), 666–672, discussion 673 (2001).
[CrossRef] [PubMed]

Shah, V. A.

M. Haeker, M. Sonka, R. Kardon, V. A. Shah, X. Wu, and M. D. Abramoff, “Automated segmentation of intraretinal layers from macular optical coherence tomography images,” Proc. SPIE 6512, 651214 (2007).
[CrossRef]

Sharon, E.

Y. Morad, E. Sharon, L. Hefetz, and P. Nemet, “Corneal thickness and curvature in normal-tension glaucoma,” Am. J. Ophthalmol. 125(2), 164–168 (1998).
[CrossRef] [PubMed]

Shekhar, R.

Y. Li, M. V. Netto, R. Shekhar, R. R. Krueger, and D. Huang, “A longitudinal study of LASIK flap and stromal thickness with high-speed optical coherence tomography,” Ophthalmology 114(6), 1124–1132e1 (2007).
[CrossRef] [PubMed]

Y. Li, R. Shekhar, and D. Huang, “Corneal pachymetry mapping with high-speed optical coherence tomography,” Ophthalmology 113(5), 792–799.e2 (2006).
[CrossRef] [PubMed]

Y. Li, R. Shekhar, and D. Huang, “Segmentation of 830- and 1310-nm LASIK corneal optical coherence tomography images,” Proc. SPIE 4684, 167–178 (2002).
[CrossRef]

Shields, M. B.

L. W. Herndon, S. A. Choudhri, T. Cox, K. F. Damji, M. B. Shields, and R. R. Allingham, “Central corneal thickness in normal, glaucomatous, and ocular hypertensive eyes,” Arch. Ophthalmol. 115(9), 1137–1141 (1997).
[PubMed]

Shimmyo, M.

M. Shimmyo, A. J. Ross, A. Moy, and R. Mostafavi, “Intraocular pressure, Goldmann applanation tension, corneal thickness, and corneal curvature in Caucasians, Asians, Hispanics, and African Americans,” Am. J. Ophthalmol. 136(4), 603–613 (2003).
[CrossRef] [PubMed]

Silverman, R. H.

D. Z. Reinstein, T. J. Archer, M. Gobbe, R. H. Silverman, and D. J. Coleman, “Epithelial thickness in the normal cornea: three-dimensional display with Artemis very high-frequency digital ultrasound,” J. Refract. Surg. 24(6), 571–581 (2008).
[PubMed]

D. Z. Reinstein, R. H. Silverman, M. J. Rondeau, and D. J. Coleman, “Epithelial and corneal thickness measurements by high-frequency ultrasound digital signal processing,” Ophthalmology 101(1), 140–146 (1994).
[PubMed]

Simpson, T. L.

N. Hutchings, T. L. Simpson, C. Hyun, A. A. Moayed, S. Hariri, L. Sorbara, and K. Bizheva, “Swelling of the human cornea revealed by high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 51(9), 4579–4584 (2010).
[CrossRef] [PubMed]

Sonka, M.

K. Lee, M. Niemeijer, M. K. Garvin, Y. H. Kwon, M. Sonka, and M. D. Abramoff, “Segmentation of the optic disc in 3-D OCT scans of the optic nerve head,” IEEE Trans. Med. Imaging 29(1), 159–168 (2010).
[CrossRef] [PubMed]

M. K. Garvin, M. D. Abràmoff, X. Wu, S. R. Russell, T. L. Burns, and M. Sonka, “Automated 3-D intraretinal layer segmentation of macular spectral-domain optical coherence tomography images,” IEEE Trans. Med. Imaging 28(9), 1436–1447 (2009).
[CrossRef] [PubMed]

M. Haeker, M. Sonka, R. Kardon, V. A. Shah, X. Wu, and M. D. Abramoff, “Automated segmentation of intraretinal layers from macular optical coherence tomography images,” Proc. SPIE 6512, 651214 (2007).
[CrossRef]

Sorbara, L.

N. Hutchings, T. L. Simpson, C. Hyun, A. A. Moayed, S. Hariri, L. Sorbara, and K. Bizheva, “Swelling of the human cornea revealed by high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 51(9), 4579–4584 (2010).
[CrossRef] [PubMed]

Spoerl, E.

M. Kohlhaas, A. G. Boehm, E. Spoerl, A. Pürsten, H. J. Grein, and L. E. Pillunat, “Effect of central corneal thickness, corneal curvature, and axial length on applanation tonometry,” Arch. Ophthalmol. 124(4), 471–476 (2006).
[CrossRef] [PubMed]

Stinson, W. G.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Suárez, E.

B. Seitz, F. Torres, A. Langenbucher, A. Behrens, and E. Suárez, “Posterior corneal curvature changes after myopic laser in situ keratomileusis,” Ophthalmology 108(4), 666–672, discussion 673 (2001).
[CrossRef] [PubMed]

Swanson, E. A.

J. A. Izatt, M. R. Hee, E. A. Swanson, C. P. Lin, D. Huang, J. S. Schuman, C. A. Puliafito, and J. G. Fujimoto, “Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography,” Arch. Ophthalmol. 112(12), 1584–1589 (1994).
[PubMed]

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Szeliski, R.

R. Szeliski, “Image alignment and stitching: a tutorial,” Found. Trends Comput. Graphics Vision 2(1), 1–104 (2006).
[CrossRef]

Tolliver, D. A.

D. A. Tolliver, I. Koutis, H. Ishikawa, J. S. Schuman, and G. L. Miller, “Automatic multiple retinal layer segmentation in spectral domain OCT scans via spectral rounding,” Invest. Ophthalmol. Vis. Sci. 49, 1878-2222 (2008).

Torres, F.

B. Seitz, F. Torres, A. Langenbucher, A. Behrens, and E. Suárez, “Posterior corneal curvature changes after myopic laser in situ keratomileusis,” Ophthalmology 108(4), 666–672, discussion 673 (2001).
[CrossRef] [PubMed]

Toth, C. A.

S. J. Chiu, X. T. Li, P. Nicholas, C. A. Toth, J. A. Izatt, and S. Farsiu, “Automatic segmentation of seven retinal layers in SDOCT images congruent with expert manual segmentation,” Opt. Express 18(18), 19413–19428 (2010).
[CrossRef] [PubMed]

S. G. Schuman, A. F. Koreishi, S. Farsiu, S. H. Jung, J. A. Izatt, and C. A. Toth, “Photoreceptor layer thinning over drusen in eyes with age-related macular degeneration imaged in vivo with spectral-domain optical coherence tomography,” Ophthalmology 116(3), 488–496e2 (2009).
[CrossRef] [PubMed]

Vrensen, G. F. J. M.

L. J. Müller, E. Pels, and G. F. J. M. Vrensen, “The specific architecture of the anterior stroma accounts for maintenance of corneal curvature,” Br. J. Ophthalmol. 85(4), 437–443 (2001).
[CrossRef] [PubMed]

Westphal, V.

S. Radhakrishnan, A. M. Rollins, J. E. Roth, S. Yazdanfar, V. Westphal, D. S. Bardenstein, and J. A. Izatt, “Real-time optical coherence tomography of the anterior segment at 1310 nm,” Arch. Ophthalmol. 119(8), 1179–1185 (2001).
[PubMed]

Wu, X.

M. K. Garvin, M. D. Abràmoff, X. Wu, S. R. Russell, T. L. Burns, and M. Sonka, “Automated 3-D intraretinal layer segmentation of macular spectral-domain optical coherence tomography images,” IEEE Trans. Med. Imaging 28(9), 1436–1447 (2009).
[CrossRef] [PubMed]

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Figures (15)

Fig. 2
Fig. 2

An example low-SNR corneal image (same OCT data as in Fig. 1.c) in which key regions and different types of imaging artifacts are labeled. Since SNR decreases with depth in SDOCT images, the regions of high and low-SNR also change. Some features, such as the hyporeflective region, appear in only a small subset of our corneal image database.

Fig. 1
Fig. 1

Corneal images of varying SNR and artifacts used in this study. (a) Corneal image with minimal artifacts. (b) Corneal image with prominent central and horizontal artifacts (see Fig. 2 for the visual description and annotation of these artifacts). (c) Corneal image with low-SNR, a prominent central artifact, and a hyporeflective region between the epithelium surface and the Bowman’s layer. (d) Corneal image with low-SNR, prominent central and horizontal artifacts, and other vertical artifacts.

Fig. 3
Fig. 3

Gradient images of Fig. 1.b. (a) Dark-to-light gradient image for segmenting the air-epithelial layer boundary. (b) Light-to-dark gradient image for segmenting the endothelial-aqueous layer boundary.

Fig. 4
Fig. 4

Outline of the corneal segmentation algorithm.

Fig. 5
Fig. 5

Reduction of the horizontal artifact. (a) Unprocessed corneal image (Fig. 1.b). (b) Corneal image (Fig. 1.b) with mitigated horizontal artifacts due to mean intensity subtraction from each row in the image.

Fig. 6
Fig. 6

Comparison of A-scan mean intensities to detect the central artifact in Fig. 1.b. The plot below the image shows the A-scan mean intensities of the image with the different regions denoted by red, dotted vertical lines. The horizontal red line is 4/3 times the mean value of the mean intensity per A-scan in Regions I and III (the vertical axis on the bottom plot does not start at zero). The black dotted lines denote the central artifact as detected by our algorithm.

Fig. 7
Fig. 7

Corneal image (Fig. 1.c) with the smoothed pilot epithelial layer boundary overlaid. The second derivative plot of the pilot epithelial layer boundary is used to detect the regions of low-SNR for the epithelium excluding the center half of the image (Region B). A second derivative below 0 indicates that there is a positive inflection in the second derivative, which should not occur for normal cornea and thus indicates that the SNR may be low at this location. A second derivative below 0 in Region B often occurs near the central artifact due to the central artifact removal step which results in a linear interpolation between both sides of the central artifact.

Fig. 8
Fig. 8

Blending mechanism smoothens the transition between extrapolated and non-extrapolated segments of the image in Fig. 1.c. (a) Segmented epithelium boundary without the blending mechanism. (b) Segmented epithelium boundary with the blending mechanism.

Fig. 9
Fig. 9

Mismatch between the pilot and the actual position of the epithelium layer boundary (manually segmented by a cornea specialist) in the original and dark-to-light gradient image (Fig. 1.c). (a) Pilot epithelium boundary (yellow) and the actual location of the epithelium boundary (blue) delineated over the original image. Note that the actual epithelium goes through the center of the brightest region of the original image. (b) Pilot and the actual epithelium boundary from (a) delineated on the gradient image. Note that the brightest region in the gradient image (b) is not the same as in (a), which results in mismatch between the two lines.

Fig. 10
Fig. 10

Method for flattening corneal images based on the air-epithelium boundary segmentation. The corneal image is circularly shifted either up or down depending on the position of the air-epithelium boundary segmentation in relation to the mean position of that segmentation. The red arrows indicate the direction and relative amount of the circular shift of each A-scan.

Fig. 11
Fig. 11

Flattened version of Fig. 1.c based on air-epithelium interface. We approximate the thickness of the center of the cornea by searching for the largest decrease in mean intensity of adjacent rows within the range of 400 – 800 µm below the air-epithelium interface (green dashed line). The differences between the mean intensity of adjacent rows in central Regions X and Y are plotted in blue on the left and right of the image, respectively. Note that Regions X and Y are denoised with predominately horizontal filters to remove noise and accentual the vertical gradients.

Fig. 12
Fig. 12

The corneal image from Fig. 1.c with the augmented air-epithelium boundary delineated in yellow. The dotted orange curves below the epithelium represent the search region for the epithelium-Bowman’s layer boundary.

Fig. 13
Fig. 13

(a) Comparison of automatic (cyan) versus expert (magenta) segmentation. (b) Comparison of trained manual (green) versus expert (magenta) segmentation.

Fig. 14
Fig. 14

a–d) The segmented corneal images of Fig. 1.a–d, respectively, in which the yellow layer is the air-epithelium interface, the magenta layer is the epithelium-Bowman’s layer interface, and the red layer is the endothelium-aqueous interface. Recall from Fig. 1 that (a) and (b) had relatively high-SNR and (c) and (d) had relatively low-SNR.

Fig. 15
Fig. 15

Segmentation of a cornea that has undergone LASIK surgery and a cornea with keratoconus. (a) Cornea after LASIK surgery with four layer interfaces segmented: the air-epithelium layer interface (yellow), the epithelium-Bowman’s layer interface (magenta), the LASIK flap (cyan), and the endothelium-aqueous interface (red). (b) Cornea with keratoconus with the yellow, magenta, and red curves representing the same interfaces as in (a).

Tables (2)

Tables Icon

Table 1 Differences in corneal layer boundary segmentation between two manual graders for 40 B-scans (Column I), as compared to the position differences between the automatic segmentation and the expert manual grader of the same 40 B-scans (Column II). Each pixel is approximately 3.4 µm in the cornea. The automatic segmentation has the same or lower mean difference and standard deviation compared to the expert than another trained manual grader.

Tables Icon

Table 2 Repeatability tests for the First Expert Manual Grader (Column I) and the Second Trained Manual Grader (Column II). Each pixel is approximately 3.4 µm in the cornea.

Equations (2)

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w a b = 2 ( g a + g b ) + w m i n
i = α β + α l a y e r p i l o t ( i ) ( β + α i ) ( β ) + l a y e r e x t r a p ( i ) ( i α ) ( β )  

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