Abstract

Keratocytes are fibroblast-like cells that maintain the optical clarity and the overall health of the cornea. The ability to measure precisely their density and spatial distribution in the cornea is important for the understanding of corneal healing processes and the diagnostics of some corneal disorders. A novel computerized approach to detection and counting of keratocyte cells from ultra high resolution optical coherence tomography (UHR-OCT) images of the human corneal stroma is presented. The corneal OCT data is first processed using a state-of-the-art despeckling algorithm to reduce the effect of speckle on detection accuracy. A thresholding strategy is then employed to allow for improved delineation of keratocyte cells by suppressing similarly shaped features in the data, followed by a second-order moment analysis to identify potential cell nuclei candidates. Finally, a local extrema strategy is used to refine the candidates to determine the locations and the number of keratocyte cells. Cell density distribution analysis was carried in 3D UHR-OCT images of the human corneal stroma, acquired in-vivo. The cell density results obtained using the proposed novel approach correlate well with previous work on computerized keratocyte cell counting from confocal microscopy images of human cornea.

© 2011 OSA

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2011 (1)

2010 (4)

J. R. Hassell and D. E. Birk, “The molecular basis of corneal transparency,” Exp. Eye Res.91(3), 326–335 (2010).
[CrossRef] [PubMed]

J. McLaren, W. Bourne, and S. Patel, “Automated assessment of keratocyte density in stromal images from theConfoScan 4 confocal microscope,” Invest. Ophthalmol. Vis. Sci.51(4), 1918–1926 (2010).
[CrossRef]

A. Wong, A. Mishra, K. Bizheva, and D. A. Clausi, “General Bayesian estimation for speckle noise reduction in optical coherence tomography retinal imagery,” Opt. Express18(8), 8338–8352 (2010).
[CrossRef] [PubMed]

L. Kagemann, G. Wollstein, H. Ishikawa, R. A. Bilonick, P. M. Brennen, L. S. Folio, M. L. Gabriele, and J. S. Schuman, “Identification and assessment of Schlemm’s canal by spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.51(8), 4054–4059 (2010).
[CrossRef] [PubMed]

2009 (3)

2008 (1)

J. W. McLaren, S. V. Patel, C. B. Nau, and W. M. Bourne, “Automated assessment of keratocyte density in clinical confocal microscopy of the corneal stroma,” J. Microsc.229(1), 21–31 (2008).
[CrossRef] [PubMed]

2007 (3)

V. Christopoulos, L. Kagemann, G. Wollstein, H. Ishikawa, M. L. Gabriele, M. Wojtkowski, V. Srinivasan, J. G. Fujimoto, J. S. Duker, D. K. Dhaliwal, and J. S. Schuman, “In vivo corneal high-speed, ultra high-resolution optical coherence tomography,” Arch. Ophthalmol.125(8), 1027–1035 (2007).
[CrossRef] [PubMed]

A. E. Desjardins, B. J. Vakoc, W. Y. Oh, S. M. R. Motaghiannezam, G. J. Tearney, and B. E. Bouma, “Angle-resolved optical coherence tomography with sequential angular selectivity for speckle reduction,” Opt. Express15(10), 6200–6209 (2007).
[CrossRef] [PubMed]

T. Jørgensen, L. Thrane, M. Mogensen, F. Pedersen, and P. Andersen, “Speckle reduction in optical coherencetomography images of human skin by a spatial diversity method,” Proc. SPIE6627, 66270P, 66270P-5 (2007).
[CrossRef]

2005 (1)

J. Kim, D. Miller, E. Kim, S. Oh, J. Oh, and T. Milner, “Optical coherence tomography speckle reduction by apartially spatially coherent source,” J. Biomed. Opt.10(6), 064034 (2005).
[CrossRef]

2004 (3)

E. Götzinger, M. Pircher, M. Sticker, A. F. Fercher, and C. K. Hitzenberger, “Measurement and imaging of birefringent properties of the human cornea with phase-resolved, polarization-sensitive optical coherence tomography,” J. Biomed. Opt.9(1), 94–102 (2004).
[CrossRef] [PubMed]

M. Popper, A. M. Morgado, M. J. Quadrado, and J. A. Van Best, “Corneal cell density measurement in vivo by scanning slit confocal microscopy: method and validation,” Ophthalmic Res.36(5), 270–276 (2004).
[CrossRef] [PubMed]

W. Drexler, “Ultrahigh-resolution optical coherence tomography,” J. Biomed. Opt.9(1), 47–74 (2004).
[CrossRef] [PubMed]

2003 (3)

A. Pizurica, W. Philips, I. Lemahieu, and M. Acheroy, “A versatile wavelet domain noise filtration technique for medical imaging,” IEEE Trans. Med. Imaging22(3), 323–331 (2003).
[CrossRef] [PubMed]

M. Pircher, E. Gotzinger, R. Leitgeb, A. F. Fercher, and C. K. Hitzenberger, “Speckle reduction in optical coherence tomography by frequency compounding,” J. Biomed. Opt.8(3), 565–569 (2003).
[CrossRef] [PubMed]

N. Iftimia, B. E. Bouma, and G. J. Tearney, “Speckle reduction in optical coherence tomography by “path length encoded” angular compounding,” J. Biomed. Opt.8(2), 260–263 (2003).
[CrossRef] [PubMed]

2002 (1)

Y. Yu and S. T. Acton, “Speckle reducing anisotropic diffusion,” IEEE Trans. Image Process.11(11), 1260–1270 (2002).
[CrossRef] [PubMed]

1999 (2)

J. Schmitt, S. Xiang, and K. Yung, “Speckle in optical coherence tomography,” J. Biomed. Opt.4(1), 95–105 (1999).
[CrossRef]

S. V. Patel, J. W. McLaren, J. J. Camp, L. R. Nelson, and W. M. Bourne, “Automated quantification of keratocyte density by using confocal microscopy in vivo,” Invest. Ophthalmol. Vis. Sci.40(2), 320–326 (1999).
[PubMed]

1998 (1)

M. C. Snyder, J. P. Bergmanson, and M. J. Doughty, “Keratocytes: no more the quiet cells,” J. Am. Optom. Assoc.69(3), 180–187 (1998).
[PubMed]

1996 (1)

A. F. Fercher, “Optical coherence tomography,” J. Biomed. Opt.1(2), 157–173 (1996).
[CrossRef]

1995 (1)

L. J. Müller, L. Pels, and G. F. Vrensen, “Novel aspects of the ultrastructural organization of human corneal keratocytes,” Invest. Ophthalmol. Vis. Sci.36(13), 2557–2567 (1995).
[PubMed]

1994 (1)

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,” Science254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

1986 (1)

J. Canny, “A computational approach to edge detection,” IEEE Trans. Pattern Anal. Mach. Intell.PAMI-8(6), 679–698 (1986).
[CrossRef] [PubMed]

Acheroy, M.

A. Pizurica, W. Philips, I. Lemahieu, and M. Acheroy, “A versatile wavelet domain noise filtration technique for medical imaging,” IEEE Trans. Med. Imaging22(3), 323–331 (2003).
[CrossRef] [PubMed]

Acton, S. T.

Y. Yu and S. T. Acton, “Speckle reducing anisotropic diffusion,” IEEE Trans. Image Process.11(11), 1260–1270 (2002).
[CrossRef] [PubMed]

Andersen, P.

T. Jørgensen, L. Thrane, M. Mogensen, F. Pedersen, and P. Andersen, “Speckle reduction in optical coherencetomography images of human skin by a spatial diversity method,” Proc. SPIE6627, 66270P, 66270P-5 (2007).
[CrossRef]

Bergmanson, J. P.

M. C. Snyder, J. P. Bergmanson, and M. J. Doughty, “Keratocytes: no more the quiet cells,” J. Am. Optom. Assoc.69(3), 180–187 (1998).
[PubMed]

Bilonick, R. A.

L. Kagemann, G. Wollstein, H. Ishikawa, R. A. Bilonick, P. M. Brennen, L. S. Folio, M. L. Gabriele, and J. S. Schuman, “Identification and assessment of Schlemm’s canal by spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.51(8), 4054–4059 (2010).
[CrossRef] [PubMed]

Birk, D. E.

J. R. Hassell and D. E. Birk, “The molecular basis of corneal transparency,” Exp. Eye Res.91(3), 326–335 (2010).
[CrossRef] [PubMed]

Bizheva, K.

Bouma, B. E.

Bourne, W.

J. McLaren, W. Bourne, and S. Patel, “Automated assessment of keratocyte density in stromal images from theConfoScan 4 confocal microscope,” Invest. Ophthalmol. Vis. Sci.51(4), 1918–1926 (2010).
[CrossRef]

Bourne, W. M.

J. W. McLaren, S. V. Patel, C. B. Nau, and W. M. Bourne, “Automated assessment of keratocyte density in clinical confocal microscopy of the corneal stroma,” J. Microsc.229(1), 21–31 (2008).
[CrossRef] [PubMed]

S. V. Patel, J. W. McLaren, J. J. Camp, L. R. Nelson, and W. M. Bourne, “Automated quantification of keratocyte density by using confocal microscopy in vivo,” Invest. Ophthalmol. Vis. Sci.40(2), 320–326 (1999).
[PubMed]

Brennen, P. M.

L. Kagemann, G. Wollstein, H. Ishikawa, R. A. Bilonick, P. M. Brennen, L. S. Folio, M. L. Gabriele, and J. S. Schuman, “Identification and assessment of Schlemm’s canal by spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.51(8), 4054–4059 (2010).
[CrossRef] [PubMed]

Camp, J. J.

S. V. Patel, J. W. McLaren, J. J. Camp, L. R. Nelson, and W. M. Bourne, “Automated quantification of keratocyte density by using confocal microscopy in vivo,” Invest. Ophthalmol. Vis. Sci.40(2), 320–326 (1999).
[PubMed]

Canny, J.

J. Canny, “A computational approach to edge detection,” IEEE Trans. Pattern Anal. Mach. Intell.PAMI-8(6), 679–698 (1986).
[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,” Science254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Chiu, S. J.

Christopoulos, V.

V. Christopoulos, L. Kagemann, G. Wollstein, H. Ishikawa, M. L. Gabriele, M. Wojtkowski, V. Srinivasan, J. G. Fujimoto, J. S. Duker, D. K. Dhaliwal, and J. S. Schuman, “In vivo corneal high-speed, ultra high-resolution optical coherence tomography,” Arch. Ophthalmol.125(8), 1027–1035 (2007).
[CrossRef] [PubMed]

Clausi, D. A.

Desjardins, A. E.

Dhaliwal, D. K.

V. Christopoulos, L. Kagemann, G. Wollstein, H. Ishikawa, M. L. Gabriele, M. Wojtkowski, V. Srinivasan, J. G. Fujimoto, J. S. Duker, D. K. Dhaliwal, and J. S. Schuman, “In vivo corneal high-speed, ultra high-resolution optical coherence tomography,” Arch. Ophthalmol.125(8), 1027–1035 (2007).
[CrossRef] [PubMed]

Doughty, M. J.

M. C. Snyder, J. P. Bergmanson, and M. J. Doughty, “Keratocytes: no more the quiet cells,” J. Am. Optom. Assoc.69(3), 180–187 (1998).
[PubMed]

Drexler, W.

W. Drexler, “Ultrahigh-resolution optical coherence tomography,” J. Biomed. Opt.9(1), 47–74 (2004).
[CrossRef] [PubMed]

Duker, J. S.

V. Christopoulos, L. Kagemann, G. Wollstein, H. Ishikawa, M. L. Gabriele, M. Wojtkowski, V. Srinivasan, J. G. Fujimoto, J. S. Duker, D. K. Dhaliwal, and J. S. Schuman, “In vivo corneal high-speed, ultra high-resolution optical coherence tomography,” Arch. Ophthalmol.125(8), 1027–1035 (2007).
[CrossRef] [PubMed]

Farsiu, S.

Fercher, A. F.

E. Götzinger, M. Pircher, M. Sticker, A. F. Fercher, and C. K. Hitzenberger, “Measurement and imaging of birefringent properties of the human cornea with phase-resolved, polarization-sensitive optical coherence tomography,” J. Biomed. Opt.9(1), 94–102 (2004).
[CrossRef] [PubMed]

M. Pircher, E. Gotzinger, R. Leitgeb, A. F. Fercher, and C. K. Hitzenberger, “Speckle reduction in optical coherence tomography by frequency compounding,” J. Biomed. Opt.8(3), 565–569 (2003).
[CrossRef] [PubMed]

A. F. Fercher, “Optical coherence tomography,” J. Biomed. Opt.1(2), 157–173 (1996).
[CrossRef]

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,” Science254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Folio, L. S.

L. Kagemann, G. Wollstein, H. Ishikawa, R. A. Bilonick, P. M. Brennen, L. S. Folio, M. L. Gabriele, and J. S. Schuman, “Identification and assessment of Schlemm’s canal by spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.51(8), 4054–4059 (2010).
[CrossRef] [PubMed]

Fujimoto, J. G.

V. Christopoulos, L. Kagemann, G. Wollstein, H. Ishikawa, M. L. Gabriele, M. Wojtkowski, V. Srinivasan, J. G. Fujimoto, J. S. Duker, D. K. Dhaliwal, and J. S. Schuman, “In vivo corneal high-speed, ultra high-resolution optical coherence tomography,” Arch. Ophthalmol.125(8), 1027–1035 (2007).
[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,” Science254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Gabriele, M. L.

L. Kagemann, G. Wollstein, H. Ishikawa, R. A. Bilonick, P. M. Brennen, L. S. Folio, M. L. Gabriele, and J. S. Schuman, “Identification and assessment of Schlemm’s canal by spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.51(8), 4054–4059 (2010).
[CrossRef] [PubMed]

V. Christopoulos, L. Kagemann, G. Wollstein, H. Ishikawa, M. L. Gabriele, M. Wojtkowski, V. Srinivasan, J. G. Fujimoto, J. S. Duker, D. K. Dhaliwal, and J. S. Schuman, “In vivo corneal high-speed, ultra high-resolution optical coherence tomography,” Arch. Ophthalmol.125(8), 1027–1035 (2007).
[CrossRef] [PubMed]

Gora, M.

Gorczynska, I.

Gotzinger, E.

M. Pircher, E. Gotzinger, R. Leitgeb, A. F. Fercher, and C. K. Hitzenberger, “Speckle reduction in optical coherence tomography by frequency compounding,” J. Biomed. Opt.8(3), 565–569 (2003).
[CrossRef] [PubMed]

Götzinger, E.

E. Götzinger, M. Pircher, M. Sticker, A. F. Fercher, and C. K. Hitzenberger, “Measurement and imaging of birefringent properties of the human cornea with phase-resolved, polarization-sensitive optical coherence tomography,” J. Biomed. Opt.9(1), 94–102 (2004).
[CrossRef] [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,” Science254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Grulkowski, I.

Hassell, J. R.

J. R. Hassell and D. E. Birk, “The molecular basis of corneal transparency,” Exp. Eye Res.91(3), 326–335 (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,” Science254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Hitzenberger, C. K.

E. Götzinger, M. Pircher, M. Sticker, A. F. Fercher, and C. K. Hitzenberger, “Measurement and imaging of birefringent properties of the human cornea with phase-resolved, polarization-sensitive optical coherence tomography,” J. Biomed. Opt.9(1), 94–102 (2004).
[CrossRef] [PubMed]

M. Pircher, E. Gotzinger, R. Leitgeb, A. F. Fercher, and C. K. Hitzenberger, “Speckle reduction in optical coherence tomography by frequency compounding,” J. Biomed. Opt.8(3), 565–569 (2003).
[CrossRef] [PubMed]

Huang, D.

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,” Science254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Huber, R.

Iftimia, N.

N. Iftimia, B. E. Bouma, and G. J. Tearney, “Speckle reduction in optical coherence tomography by “path length encoded” angular compounding,” J. Biomed. Opt.8(2), 260–263 (2003).
[CrossRef] [PubMed]

Ishikawa, H.

L. Kagemann, G. Wollstein, H. Ishikawa, R. A. Bilonick, P. M. Brennen, L. S. Folio, M. L. Gabriele, and J. S. Schuman, “Identification and assessment of Schlemm’s canal by spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.51(8), 4054–4059 (2010).
[CrossRef] [PubMed]

V. Christopoulos, L. Kagemann, G. Wollstein, H. Ishikawa, M. L. Gabriele, M. Wojtkowski, V. Srinivasan, J. G. Fujimoto, J. S. Duker, D. K. Dhaliwal, and J. S. Schuman, “In vivo corneal high-speed, ultra high-resolution optical coherence tomography,” Arch. Ophthalmol.125(8), 1027–1035 (2007).
[CrossRef] [PubMed]

Izatt, J. A.

F. LaRocca, S. J. Chiu, R. P. McNabb, A. N. Kuo, J. A. Izatt, and S. Farsiu, “Robust automatic segmentation of corneal layer boundaries in SDOCT images using graph theory and dynamic programming,” Biomed. Opt. Express2(6), 1524–1538 (2011).
[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]

Jørgensen, T.

T. Jørgensen, L. Thrane, M. Mogensen, F. Pedersen, and P. Andersen, “Speckle reduction in optical coherencetomography images of human skin by a spatial diversity method,” Proc. SPIE6627, 66270P, 66270P-5 (2007).
[CrossRef]

Kagemann, L.

L. Kagemann, G. Wollstein, H. Ishikawa, R. A. Bilonick, P. M. Brennen, L. S. Folio, M. L. Gabriele, and J. S. Schuman, “Identification and assessment of Schlemm’s canal by spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.51(8), 4054–4059 (2010).
[CrossRef] [PubMed]

V. Christopoulos, L. Kagemann, G. Wollstein, H. Ishikawa, M. L. Gabriele, M. Wojtkowski, V. Srinivasan, J. G. Fujimoto, J. S. Duker, D. K. Dhaliwal, and J. S. Schuman, “In vivo corneal high-speed, ultra high-resolution optical coherence tomography,” Arch. Ophthalmol.125(8), 1027–1035 (2007).
[CrossRef] [PubMed]

Kaluzny, B. J.

Karnowski, K.

Kim, E.

J. Kim, D. Miller, E. Kim, S. Oh, J. Oh, and T. Milner, “Optical coherence tomography speckle reduction by apartially spatially coherent source,” J. Biomed. Opt.10(6), 064034 (2005).
[CrossRef]

Kim, J.

J. Kim, D. Miller, E. Kim, S. Oh, J. Oh, and T. Milner, “Optical coherence tomography speckle reduction by apartially spatially coherent source,” J. Biomed. Opt.10(6), 064034 (2005).
[CrossRef]

Kowalczyk, A.

Kuo, A. N.

LaRocca, F.

Leitgeb, R.

M. Pircher, E. Gotzinger, R. Leitgeb, A. F. Fercher, and C. K. Hitzenberger, “Speckle reduction in optical coherence tomography by frequency compounding,” J. Biomed. Opt.8(3), 565–569 (2003).
[CrossRef] [PubMed]

Lemahieu, I.

A. Pizurica, W. Philips, I. Lemahieu, and M. Acheroy, “A versatile wavelet domain noise filtration technique for medical imaging,” IEEE Trans. Med. Imaging22(3), 323–331 (2003).
[CrossRef] [PubMed]

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,” Science254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Marcos, S.

McLaren, J.

J. McLaren, W. Bourne, and S. Patel, “Automated assessment of keratocyte density in stromal images from theConfoScan 4 confocal microscope,” Invest. Ophthalmol. Vis. Sci.51(4), 1918–1926 (2010).
[CrossRef]

McLaren, J. W.

J. W. McLaren, S. V. Patel, C. B. Nau, and W. M. Bourne, “Automated assessment of keratocyte density in clinical confocal microscopy of the corneal stroma,” J. Microsc.229(1), 21–31 (2008).
[CrossRef] [PubMed]

S. V. Patel, J. W. McLaren, J. J. Camp, L. R. Nelson, and W. M. Bourne, “Automated quantification of keratocyte density by using confocal microscopy in vivo,” Invest. Ophthalmol. Vis. Sci.40(2), 320–326 (1999).
[PubMed]

McNabb, R. P.

Miller, D.

J. Kim, D. Miller, E. Kim, S. Oh, J. Oh, and T. Milner, “Optical coherence tomography speckle reduction by apartially spatially coherent source,” J. Biomed. Opt.10(6), 064034 (2005).
[CrossRef]

Milner, T.

J. Kim, D. Miller, E. Kim, S. Oh, J. Oh, and T. Milner, “Optical coherence tomography speckle reduction by apartially spatially coherent source,” J. Biomed. Opt.10(6), 064034 (2005).
[CrossRef]

Mishra, A.

Mogensen, M.

T. Jørgensen, L. Thrane, M. Mogensen, F. Pedersen, and P. Andersen, “Speckle reduction in optical coherencetomography images of human skin by a spatial diversity method,” Proc. SPIE6627, 66270P, 66270P-5 (2007).
[CrossRef]

Morgado, A. M.

M. Popper, A. M. Morgado, M. J. Quadrado, and J. A. Van Best, “Corneal cell density measurement in vivo by scanning slit confocal microscopy: method and validation,” Ophthalmic Res.36(5), 270–276 (2004).
[CrossRef] [PubMed]

Motaghiannezam, S. M. R.

Müller, L. J.

L. J. Müller, L. Pels, and G. F. Vrensen, “Novel aspects of the ultrastructural organization of human corneal keratocytes,” Invest. Ophthalmol. Vis. Sci.36(13), 2557–2567 (1995).
[PubMed]

Nau, C. B.

J. W. McLaren, S. V. Patel, C. B. Nau, and W. M. Bourne, “Automated assessment of keratocyte density in clinical confocal microscopy of the corneal stroma,” J. Microsc.229(1), 21–31 (2008).
[CrossRef] [PubMed]

Nelson, L. R.

S. V. Patel, J. W. McLaren, J. J. Camp, L. R. Nelson, and W. M. Bourne, “Automated quantification of keratocyte density by using confocal microscopy in vivo,” Invest. Ophthalmol. Vis. Sci.40(2), 320–326 (1999).
[PubMed]

Oh, J.

J. Kim, D. Miller, E. Kim, S. Oh, J. Oh, and T. Milner, “Optical coherence tomography speckle reduction by apartially spatially coherent source,” J. Biomed. Opt.10(6), 064034 (2005).
[CrossRef]

Oh, S.

J. Kim, D. Miller, E. Kim, S. Oh, J. Oh, and T. Milner, “Optical coherence tomography speckle reduction by apartially spatially coherent source,” J. Biomed. Opt.10(6), 064034 (2005).
[CrossRef]

Oh, W. Y.

Patel, S.

J. McLaren, W. Bourne, and S. Patel, “Automated assessment of keratocyte density in stromal images from theConfoScan 4 confocal microscope,” Invest. Ophthalmol. Vis. Sci.51(4), 1918–1926 (2010).
[CrossRef]

Patel, S. V.

J. W. McLaren, S. V. Patel, C. B. Nau, and W. M. Bourne, “Automated assessment of keratocyte density in clinical confocal microscopy of the corneal stroma,” J. Microsc.229(1), 21–31 (2008).
[CrossRef] [PubMed]

S. V. Patel, J. W. McLaren, J. J. Camp, L. R. Nelson, and W. M. Bourne, “Automated quantification of keratocyte density by using confocal microscopy in vivo,” Invest. Ophthalmol. Vis. Sci.40(2), 320–326 (1999).
[PubMed]

Pedersen, F.

T. Jørgensen, L. Thrane, M. Mogensen, F. Pedersen, and P. Andersen, “Speckle reduction in optical coherencetomography images of human skin by a spatial diversity method,” Proc. SPIE6627, 66270P, 66270P-5 (2007).
[CrossRef]

Pels, L.

L. J. Müller, L. Pels, and G. F. Vrensen, “Novel aspects of the ultrastructural organization of human corneal keratocytes,” Invest. Ophthalmol. Vis. Sci.36(13), 2557–2567 (1995).
[PubMed]

Philips, W.

A. Pizurica, W. Philips, I. Lemahieu, and M. Acheroy, “A versatile wavelet domain noise filtration technique for medical imaging,” IEEE Trans. Med. Imaging22(3), 323–331 (2003).
[CrossRef] [PubMed]

Pircher, M.

E. Götzinger, M. Pircher, M. Sticker, A. F. Fercher, and C. K. Hitzenberger, “Measurement and imaging of birefringent properties of the human cornea with phase-resolved, polarization-sensitive optical coherence tomography,” J. Biomed. Opt.9(1), 94–102 (2004).
[CrossRef] [PubMed]

M. Pircher, E. Gotzinger, R. Leitgeb, A. F. Fercher, and C. K. Hitzenberger, “Speckle reduction in optical coherence tomography by frequency compounding,” J. Biomed. Opt.8(3), 565–569 (2003).
[CrossRef] [PubMed]

Pizurica, A.

A. Pizurica, W. Philips, I. Lemahieu, and M. Acheroy, “A versatile wavelet domain noise filtration technique for medical imaging,” IEEE Trans. Med. Imaging22(3), 323–331 (2003).
[CrossRef] [PubMed]

Popper, M.

M. Popper, A. M. Morgado, M. J. Quadrado, and J. A. Van Best, “Corneal cell density measurement in vivo by scanning slit confocal microscopy: method and validation,” Ophthalmic Res.36(5), 270–276 (2004).
[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,” Science254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Puvanathasan, P.

Quadrado, M. J.

M. Popper, A. M. Morgado, M. J. Quadrado, and J. A. Van Best, “Corneal cell density measurement in vivo by scanning slit confocal microscopy: method and validation,” Ophthalmic Res.36(5), 270–276 (2004).
[CrossRef] [PubMed]

Schmitt, J.

J. Schmitt, S. Xiang, and K. Yung, “Speckle in optical coherence tomography,” J. Biomed. Opt.4(1), 95–105 (1999).
[CrossRef]

Schuman, J. S.

L. Kagemann, G. Wollstein, H. Ishikawa, R. A. Bilonick, P. M. Brennen, L. S. Folio, M. L. Gabriele, and J. S. Schuman, “Identification and assessment of Schlemm’s canal by spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.51(8), 4054–4059 (2010).
[CrossRef] [PubMed]

V. Christopoulos, L. Kagemann, G. Wollstein, H. Ishikawa, M. L. Gabriele, M. Wojtkowski, V. Srinivasan, J. G. Fujimoto, J. S. Duker, D. K. Dhaliwal, and J. S. Schuman, “In vivo corneal high-speed, ultra high-resolution optical coherence tomography,” Arch. Ophthalmol.125(8), 1027–1035 (2007).
[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,” Science254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Snyder, M. C.

M. C. Snyder, J. P. Bergmanson, and M. J. Doughty, “Keratocytes: no more the quiet cells,” J. Am. Optom. Assoc.69(3), 180–187 (1998).
[PubMed]

Srinivasan, V.

V. Christopoulos, L. Kagemann, G. Wollstein, H. Ishikawa, M. L. Gabriele, M. Wojtkowski, V. Srinivasan, J. G. Fujimoto, J. S. Duker, D. K. Dhaliwal, and J. S. Schuman, “In vivo corneal high-speed, ultra high-resolution optical coherence tomography,” Arch. Ophthalmol.125(8), 1027–1035 (2007).
[CrossRef] [PubMed]

Sticker, M.

E. Götzinger, M. Pircher, M. Sticker, A. F. Fercher, and C. K. Hitzenberger, “Measurement and imaging of birefringent properties of the human cornea with phase-resolved, polarization-sensitive optical coherence tomography,” J. Biomed. Opt.9(1), 94–102 (2004).
[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,” Science254(5035), 1178–1181 (1991).
[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,” Science254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Szkulmowski, M.

Szlag, D.

Tearney, G. J.

Thrane, L.

T. Jørgensen, L. Thrane, M. Mogensen, F. Pedersen, and P. Andersen, “Speckle reduction in optical coherencetomography images of human skin by a spatial diversity method,” Proc. SPIE6627, 66270P, 66270P-5 (2007).
[CrossRef]

Vakoc, B. J.

Van Best, J. A.

M. Popper, A. M. Morgado, M. J. Quadrado, and J. A. Van Best, “Corneal cell density measurement in vivo by scanning slit confocal microscopy: method and validation,” Ophthalmic Res.36(5), 270–276 (2004).
[CrossRef] [PubMed]

Vrensen, G. F.

L. J. Müller, L. Pels, and G. F. Vrensen, “Novel aspects of the ultrastructural organization of human corneal keratocytes,” Invest. Ophthalmol. Vis. Sci.36(13), 2557–2567 (1995).
[PubMed]

Wojtkowski, M.

Wollstein, G.

L. Kagemann, G. Wollstein, H. Ishikawa, R. A. Bilonick, P. M. Brennen, L. S. Folio, M. L. Gabriele, and J. S. Schuman, “Identification and assessment of Schlemm’s canal by spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.51(8), 4054–4059 (2010).
[CrossRef] [PubMed]

V. Christopoulos, L. Kagemann, G. Wollstein, H. Ishikawa, M. L. Gabriele, M. Wojtkowski, V. Srinivasan, J. G. Fujimoto, J. S. Duker, D. K. Dhaliwal, and J. S. Schuman, “In vivo corneal high-speed, ultra high-resolution optical coherence tomography,” Arch. Ophthalmol.125(8), 1027–1035 (2007).
[CrossRef] [PubMed]

Wong, A.

Xiang, S.

J. Schmitt, S. Xiang, and K. Yung, “Speckle in optical coherence tomography,” J. Biomed. Opt.4(1), 95–105 (1999).
[CrossRef]

Yu, Y.

Y. Yu and S. T. Acton, “Speckle reducing anisotropic diffusion,” IEEE Trans. Image Process.11(11), 1260–1270 (2002).
[CrossRef] [PubMed]

Yung, K.

J. Schmitt, S. Xiang, and K. Yung, “Speckle in optical coherence tomography,” J. Biomed. Opt.4(1), 95–105 (1999).
[CrossRef]

Arch. Ophthalmol. (2)

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]

V. Christopoulos, L. Kagemann, G. Wollstein, H. Ishikawa, M. L. Gabriele, M. Wojtkowski, V. Srinivasan, J. G. Fujimoto, J. S. Duker, D. K. Dhaliwal, and J. S. Schuman, “In vivo corneal high-speed, ultra high-resolution optical coherence tomography,” Arch. Ophthalmol.125(8), 1027–1035 (2007).
[CrossRef] [PubMed]

Biomed. Opt. Express (1)

Exp. Eye Res. (1)

J. R. Hassell and D. E. Birk, “The molecular basis of corneal transparency,” Exp. Eye Res.91(3), 326–335 (2010).
[CrossRef] [PubMed]

IEEE Trans. Image Process. (1)

Y. Yu and S. T. Acton, “Speckle reducing anisotropic diffusion,” IEEE Trans. Image Process.11(11), 1260–1270 (2002).
[CrossRef] [PubMed]

IEEE Trans. Med. Imaging (1)

A. Pizurica, W. Philips, I. Lemahieu, and M. Acheroy, “A versatile wavelet domain noise filtration technique for medical imaging,” IEEE Trans. Med. Imaging22(3), 323–331 (2003).
[CrossRef] [PubMed]

IEEE Trans. Pattern Anal. Mach. Intell. (1)

J. Canny, “A computational approach to edge detection,” IEEE Trans. Pattern Anal. Mach. Intell.PAMI-8(6), 679–698 (1986).
[CrossRef] [PubMed]

Invest. Ophthalmol. Vis. Sci. (4)

L. Kagemann, G. Wollstein, H. Ishikawa, R. A. Bilonick, P. M. Brennen, L. S. Folio, M. L. Gabriele, and J. S. Schuman, “Identification and assessment of Schlemm’s canal by spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.51(8), 4054–4059 (2010).
[CrossRef] [PubMed]

S. V. Patel, J. W. McLaren, J. J. Camp, L. R. Nelson, and W. M. Bourne, “Automated quantification of keratocyte density by using confocal microscopy in vivo,” Invest. Ophthalmol. Vis. Sci.40(2), 320–326 (1999).
[PubMed]

L. J. Müller, L. Pels, and G. F. Vrensen, “Novel aspects of the ultrastructural organization of human corneal keratocytes,” Invest. Ophthalmol. Vis. Sci.36(13), 2557–2567 (1995).
[PubMed]

J. McLaren, W. Bourne, and S. Patel, “Automated assessment of keratocyte density in stromal images from theConfoScan 4 confocal microscope,” Invest. Ophthalmol. Vis. Sci.51(4), 1918–1926 (2010).
[CrossRef]

J. Am. Optom. Assoc. (1)

M. C. Snyder, J. P. Bergmanson, and M. J. Doughty, “Keratocytes: no more the quiet cells,” J. Am. Optom. Assoc.69(3), 180–187 (1998).
[PubMed]

J. Biomed. Opt. (7)

J. Kim, D. Miller, E. Kim, S. Oh, J. Oh, and T. Milner, “Optical coherence tomography speckle reduction by apartially spatially coherent source,” J. Biomed. Opt.10(6), 064034 (2005).
[CrossRef]

M. Pircher, E. Gotzinger, R. Leitgeb, A. F. Fercher, and C. K. Hitzenberger, “Speckle reduction in optical coherence tomography by frequency compounding,” J. Biomed. Opt.8(3), 565–569 (2003).
[CrossRef] [PubMed]

N. Iftimia, B. E. Bouma, and G. J. Tearney, “Speckle reduction in optical coherence tomography by “path length encoded” angular compounding,” J. Biomed. Opt.8(2), 260–263 (2003).
[CrossRef] [PubMed]

E. Götzinger, M. Pircher, M. Sticker, A. F. Fercher, and C. K. Hitzenberger, “Measurement and imaging of birefringent properties of the human cornea with phase-resolved, polarization-sensitive optical coherence tomography,” J. Biomed. Opt.9(1), 94–102 (2004).
[CrossRef] [PubMed]

A. F. Fercher, “Optical coherence tomography,” J. Biomed. Opt.1(2), 157–173 (1996).
[CrossRef]

W. Drexler, “Ultrahigh-resolution optical coherence tomography,” J. Biomed. Opt.9(1), 47–74 (2004).
[CrossRef] [PubMed]

J. Schmitt, S. Xiang, and K. Yung, “Speckle in optical coherence tomography,” J. Biomed. Opt.4(1), 95–105 (1999).
[CrossRef]

J. Microsc. (1)

J. W. McLaren, S. V. Patel, C. B. Nau, and W. M. Bourne, “Automated assessment of keratocyte density in clinical confocal microscopy of the corneal stroma,” J. Microsc.229(1), 21–31 (2008).
[CrossRef] [PubMed]

Ophthalmic Res. (1)

M. Popper, A. M. Morgado, M. J. Quadrado, and J. A. Van Best, “Corneal cell density measurement in vivo by scanning slit confocal microscopy: method and validation,” Ophthalmic Res.36(5), 270–276 (2004).
[CrossRef] [PubMed]

Opt. Express (5)

Proc. SPIE (1)

T. Jørgensen, L. Thrane, M. Mogensen, F. Pedersen, and P. Andersen, “Speckle reduction in optical coherencetomography images of human skin by a spatial diversity method,” Proc. SPIE6627, 66270P, 66270P-5 (2007).
[CrossRef]

Science (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,” Science254(5035), 1178–1181 (1991).
[CrossRef] [PubMed]

Other (2)

J. A. Eichel, A. K. Mishra, D. A. Clausi, P. W. Fieguth, and K. K. Bizheva, “A novel algorithm for extraction ofthe layers of the cornea,” in 2009 Canadian Conference on Computer and Robot Vision (IEEE Computer Society,2009), pp. 313-320.

A. Noble, “Descriptions of image surfaces,” Ph.D. thesis (Oxford University, 1989).

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Figures (8)

Fig. 1
Fig. 1

A representative UHR-OCT cross-sectional image of healthy human cornea acquired in-vivo (A). Ep - epithelium, BM - Bowman’s membrane; S - stroma; DEC -Descemet’s - Endothelium complex layer. Red arrow mark highly reflective spots in the stroma. A representative confocal en-face image of healthy human cornea (B). Red arrows mark keratocyte cells.

Fig. 2
Fig. 2

Step-by-step flowchart of the novel cell detection and counting approach

Fig. 3
Fig. 3

Original (A) and despeckled (B) human corneal UHR-OCT images.

Fig. 4
Fig. 4

An example of the thresholded data.

Fig. 5
Fig. 5

An example of a saliency map computed from thresholded data.

Fig. 6
Fig. 6

Illustrative example of non-maximum suppression strategy. Scanning through the set of keratocyte cell candidates, only the candidates with the highest saliency value within a local neighbourhood are selected as part of the final set of keratocyte cells used for counting. For example, in the bottom-right yellow square, while there are two immediate peaks (i.e., with saliency values of 5 and 6), only the point with saliency value of 6 is selected as part of the final set of keratocyte cells as they both represent the same keratocyte cell.

Fig. 7
Fig. 7

A representative unprocessed UHR-OCT image of healthy human cornea (A). Same image with identified and counted cells, marked with yellow squares (B).

Fig. 8
Fig. 8

Cell density plots computed for each three-dimensional stack of UHR-OCT corneal tomograms as a function of depth in the corneal stroma.

Equations (10)

Equations on this page are rendered with MathJax. Learn more.

m ( x _ ) = i ( x _ ) n ( x _ ) .
log m ( x _ ) = m l ( x _ ) = log [ i ( x _ ) n ( x _ ) ] = log { i ( x _ ) } + log { n ( x _ ) } = i l ( x _ ) + n l ( x _ ) .
i ^ ( x _ ) = exp [ p ( i l ( x _ ) | m l ( x _ ) ) i l ( x _ ) d i l ( x _ ) ] .
p ^ ( i l ( x _ ) | m l ( x _ ) ) = p * ( i l ( x _ ) | m l ( x _ ) ) p * ( i l ( x _ ) | m l ( x _ ) ) d i l ( x _ ) ,
p * ( i l ( x _ ) | m l ( x _ ) ) = 1 2 π k exp ( 1 2 σ ( m l ( x _ ) m l ( x _ k ) ) 2 ) exp ( 1 2 ( i l m l ( x _ k ) ) 2 ) ,
i Th ( x _ ) = { α , if i ( x _ ) α i ( x _ ) , if i ( x _ ) < α
Φ i Th = [ { Δ x i Th ( x _ ) } 2 { Δ x i Th ( x _ ) } { Δ y i Th ( x _ ) } { Δ x i Th ( x _ ) } { Δ y i Th ( x _ ) } { Δ y i Th ( x _ ) } 2 ]
ρ i Th ( x _ ) = det ( Φ i Th ) trace ( Φ i Th )
det ( Φ i Th ) = { Δ x i Th ( x _ ) } 2 { Δ y i Th ( x _ ) } 2 ( { Δ x i Th ( x _ ) } { Δ y i Th ( x _ ) } ) 2
trace ( Φ i Th ) = { Δ x i Th ( x _ ) } 2 + { Δ y i Th ( x _ ) } 2

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