We present a novel polarization sensitive optical coherence tomography (PS-OCT) system with an integrated retinal tracker. The tracking operates at up to 60 Hz, correcting PS-OCT scanning positions during the acquisition to avoid artifacts caused by eye motion. To demonstrate the practical performance of the system, we imaged several healthy volunteers and patients with AMD both with B-scan repetitions for frame averaging and with 3D raster scans. Under large retinal motions with up to 1 mm amplitude at 0.5 ~a few Hz frequency range, motion artifact suppression in the PS-OCT images as well as standard deviation noise reduction in the frame averaged retardation images are presented. References and links1. M. R. Hee, D. Huang, E. A. Swanson, and J. G. Fujimoto, "Polarization-Sensitive Low-Coherence Reflectometer for Birefringence Characterization and Ranging," J. Opt. Soc. Am. B 9(6), 903-908 (1992). 2. J. F. de Boer, T. E. Milner, M. J. C. van Gemert, and J. S. Nelson, "Two-dimensional birefringence imaging in biological tissue by polarization-sensitive optical coherence tomography," Opt. Lett. 22(12), 934-936 (1997). 3. J. F. De Boer, S. M. Srinivas, A. Malekafzali, Z. P. Chen, and J. S. Nelson, "Imaging thermally damaged tissue by polarization sensitive optical coherence tomography," Opt. Express 3(6), 212-218 (1998). 4. J. F. de Boer, T. E. Milner, and J. S. Nelson, "Determination of the depth-resolved Stokes parameters of light backscattered from turbid media by use of polarization-sensitive optical coherence tomography," Opt. Lett. 24(5), 300-302 (1999). 5. C. K. Hitzenberger, E. Goetzinger, M. Sticker, M. Pircher, and A. F. Fercher, "Measurement and imaging of birefringence and optic axis orientation by phase resolved polarization sensitive optical coherence tomography," Opt. Express 9(13), 780-790 (2001 Hitzenberger, "Value of polarisation-sensitive optical coherence tomography in diseases affecting the retinal pigment epithelium," Br. J. Ophthalmol. 92(2), 204-209 (2008). 18. C. Ahlers, E. Götzinger, M. Pircher, I. Golbaz, F. Prager, C. Schütze, B. Baumann, C. K. Hitzenberger, and U.Schmidt-Erfurth, "Imaging of the retinal pigment epithelium in age-related macular degeneration using polarization-sensitive optical coherence tomography," Invest. Ophthalmol. Vis. Sci. 51(4), 2149-2157 (2010). 36. E. Götzinger, B. Baumann, M. Pircher, and C. K. Hitzenberger, "Polarization maintaining fiber based ultra-high resolution spectral domain polarization sensitive optical coherence tomography," Opt. Express 17(25), 22704-22717 (2009

Abstract:We present a new semi-automatic processing method for retinal nerve fiber bundle tracing based on polarization sensitive optical coherence tomography (PS-OCT) data sets. The method for tracing is based on a nerve fiber orientation map that covers the fovea and optic nerve head (ONH) regions. In order to generate the orientation map, two types of information are used: optic axis orientation based on polarization data, and complementary information obtained from nerve fiber layer (NFL) local thickness variation to reveal fiber bundle structures around the fovea. The corresponding two orientation maps are fused into a combined fiber orientation map. En face maps of NFL retardation, thickness, and unitdepth-retardation (UDR, equivalent to birefringence) are transformed into "along-trace" maps by using the obtained traces of the nerve fiber bundles. The method is demonstrated in the eyes of healthy volunteers, and as an example of further analyses utilizing this method, maps illustrating the gradients of NFL retardation, thickness, and UDR are demonstrated. References and links1. S. C. Pollock and N. R. Miller, "The Retinal Nerve Fiber Layer," Int. Ophthalmol. Clin. 26(4), 201-221 (1986). 2. T. E. Ogden, "Nerve fiber layer of the primate retina: morphometric analysis," Invest. Ophthalmol. Vis. Sci.25(1), 19-29 (1984). 3. X. R. Huang, "Polarization properties of the retinal nerve fiber layer," Bull. Soc. Belge Ophtalmol. 302, 71-88 (2006). 4. H. A. Quigley, E. M. Addicks, and W. R. Green, "Optic nerve damage in human glaucoma. III. Quantitative correlation of nerve fiber loss and visual field defect in glaucoma, ischemic neuropathy, papilledema, and toxic neuropathy," Arch. Ophthalmol. 100(1), 135-146 (1982).

Fungal diseases in immunocompromised hosts pose significant threats to their prognoses. An accurate diagnosis and identification of the fungal pathogens causing the infection are critical to determine the proper therapeutic interventions, but these are often not achieved, due to difficulties with isolation and morphological identification. In an effort to ultimately carry out the simultaneous detection of all human pathogenic microbes, we developed a simple system to identify 26 clinically important fungi by using a combination of PCR amplification and DNA microarray assay (designated PCR-DM), in which PCR-amplified DNA from the internal transcribed spacer region of the rRNA gene was hybridized to a DNA microarray fabricated with species-specific probes sets using the Bubble Jet technology. PCR-DM reliably identified all 26 reference strains; hence, we applied it to cases of onychomycosis, taking advantage of the accessibility of tissue from skin. PCR-DM detected fungal DNA and identified pathogens in 92% of 106 microscopy-confirmed onychomycosis specimens. In contrast, culture was successful for only 36 specimens (34%), 3 of which had results inconsistent with the results of PCR-DM, but sequence analysis of the isolates proved that the PCR-DM result was correct. Thus, PCR-DM provides a powerful method to identify pathogenic fungi with high sensitivity and speed directly from tissue specimens, and this concept could be applied to other fungal or nonfungal infectious human diseases in less accessible anatomical sites.

Measurement and imaging of depolarization by polarization-sensitive optical coherence tomography (PS-OCT) requires averaging of Stokes vector elements within two- or three-dimensional (3-D) evaluation windows to obtain the degree of polarization uniformity (DOPU). By use of a PS-OCT system with an integrated retinal tracker, we analyze optimum conditions for depolarization imaging, data processing, and segmentation of depolarizing tissue in the human retina. The trade-offs between figures of merit like DOPU imaging sensitivity, efficiency, and susceptibility are evaluated in terms of 3-D resolution. The results are used for a new, detailed interpretation of PS-OCT high-resolution images of the human retinal pigment epithelium and Bruch’s membrane.

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