With optical coherence tomography (OCT), doctors can obtain clear tomography
layer structures of retina．To automatically extract the contour of the retinal sub-layers
through image segmentation is a basic issue to the application of OCT in retinal diseases
diagnosis. A multi-step approach, which includes the filtering, peak detection, Snake
model, greedy algorithm and spline interpolation, was devised. Therefore, we realized the
automatic segmentation of retinal layers and quantitative measurement of the retinal
thickness. The method was successfully applied on a database of 24 images of normal people
’s eyes. The result, which the automated thickness measurements derived by this algorithm
was compared with thickness measurements from manually marked boundaries, indicated that
this method had a good agreement with manually marked method. In conclusion, the proposed
approach is promising for investigating for retinal variability studies.

［1］Huang D, Swanson EA, Lin CP, et al. Optical coherence tomography ［J］. Science, 1991,
254(5035):1178-1181.
［2］Greenfield DS, Bagga H, Knighton RW. Macular thickness changes in glaucomatous optic
neuropathy detected using optical coherence tomography ［J］. Arch Ophthalmol, 2003, 121
(1): 41-46.
［3］Costa RA, Skaf M, Luiz AS M, et al. Retinal assessment using optical coherence
tomography ［J］. Prog in Ret and Eye Rese, 2006, 25(3)：325-353.
［4］Ishikawa H, Stein DM, Wollstein G, et al. Macular Segmentation with Optical Coherence
Tomography ［J］. Invest Ophthalmol Vis Sci, 2005, 46(6):2012-2017.
［5］Bagci AM, Shahidi M, Ansari R, et al. Thickness Profile of Retinal Layers by Optical
Coherence Tomography Image Segmentation ［J］. Am J Ophthalmol, 2008,146(5) :679-687.
［6］Rossant F, Ghorbel I, Bloch I, et al. Automated Segmentation of Retinal Layers in OCT
Imaging and Derived Ophthalmic Measures ［R］. Proceedings of the Sixth IEEE international
conference on Symposium on Biomedical Imaging: From Nano to Macro, 2009: 1370-1373.
［7］Legarreta JE, Gregori G, Punjabi OS, et al. Macular thickness measurements in normal
eyes using spectral domain optical coherence tomography［J］. Oph Surg, Las & Imag, 2008,
39(4 Suppl): S43-49. 
［8］Baroni M, Fortunat P, Torre LA. Towards Quantitative Analysis of Retinal Features in
Optical Coherence Tomography ［J］. Med Eng & Phys, 2007, 29(4): 432-441.
［9］Kass M, Witkin A, Terzopoulos D. Snakes: Active Contour Models ［J］. Inter Jo of Comp
Vis, 1987, 1(4): 321-331.
［10］Williams DJ, Shah M. A fast algorithm for active contours and curvature estimation ［
J］. CVGIP: Imag Underst, 1992, 55(1):14-26.
［11］Koozekanani D, Boyer K, Roberts C. Retinal thickness measurements from optical
coherence tomography using a markov boundary model ［J］. IEEE transaction on medical
imaging, 2001,20( 9): 900-916.