Thursday, October 14, 2010

Journal Article: Wettability Characterization by OCT

Tapio Fabritius (Oulu University, Finland) recently published a paper in Optics Express in which the authors investigated the utility of optical coherence tomography (OCT) for the characterization of wettability of materials. The study presented was a collaboration between Oulu University and Computational Optics Group at the University of Tsukuba.
In the particular demonstration in this paper, a glycerol droplet on a rough surface was characterized, and the contact angles between them were automatically obtained.

The details are published in the following Optics Express paper.

Wednesday, June 16, 2010

Journal Article: Full Range Polarization Sensitive OCT at 1-Micron

Our colleague Masahiro Yamanari recently reported a new polarization sensitive optical coherence tomography (PS-OCT) for retinal and choroidal imaging. This new PS-OCT utilized a probe beam with 1-micron wavelength enabled high-penetration to the choroid, and a full range measurement scheme based on the modulation of reference beam of OCT (BM-scan). This system enables detailed investigation of birefringence property of the deep posterior eye.
After all, this OCT possesses a depth measurement range of 5.3 micrometers in air, a depth resolution of 11.4 micrometers in tissue, and a measurement speed of 30,000 depth-scan/sec. The intensity ratio between an OCT signal and its suppressed mirror signal was found to be 40.5 dB.
This PS-OCT is the first demonstration of 1-um PS-OCT with a clinically useful depth measurement range.
The details are available in the following Optics Express paper.

Citation: M. Yamanari, S. Makita, Y. Lim, and Y. Yasuno, "Full-range polarization-sensitive swept-source optical coherence tomography by simultaneous transversal and spectral modulation," Opt. Express 18, 13964-13980 (2010).

Thursday, April 29, 2010

Adaptive Optics Optical Coherence Tomography at One-Micron

Our colleague Kazuhiro Kurokawa recently reported adaptive optics optical coherence tomography (AO-OCT) for posterior eye imaging. This AO-OCT uses one-micrometer wavelength probe, and is the world first demonstration of high-penetration AO-OCT.
In vivo measurement of human normal subject was performed. The OCT image clearly shows the crosssections of optic nerve fiber bundles as well as the interface between the choroid and sclera.

The details are reported in Optics Express.

Saturday, January 23, 2010

Photonics West Bigins

The biggest annual event of OCT community begins. BiOS, a part of SPIE Photonics West starts on Jun. 23rd. in San Francisco. Almost all members of COG are now rushing into that city. We have 7 oral presentations including 6 from our core member and 1 from our collaborator. See this page to see the abstracts and add our presentations to your conference agenda. Come and see our talks!

Saturday 23rd
  • [2:00pm-2:15pm, Room 306] S. Makita et al., "High-sensitive blood flow imaging of the retina and choroid by using double-beam optical coherence angiography."
  • [5:00pm-5:15pm, Room 306] Y. Lim et al., "Polarization Sensitive Corneal and Anterior Segment Swept-Source Optical Coherence Tomography."
  • [5:15pm-5:30pm, Room 306] A. Miyazawa et al., "Tissue discrimination in anterior eye using three optical parameters obtained by polarization sensitive optical coherence tomography."
Sunday 24th
  • [5:30pm-5:45pm, Room 306] Y. Ikuno et al., "Clinical application of high-penetration optical coherence tomography using 1060-nm wevelength."
Monday 25th
  • [1:00pm-1:15pm, Room 303] K. Kurokawa et al., "Adaptive optics spectral domain optical coherence tomography with one-micrometer light source."
Tuesday 26th
  • [11:15am-11:30am] F. Jaillon et al., "BM-mode scanning with parabolic phase modulation for full range Doppler optical tomography."
Wednesday 27th
  • [8:45am-9:00am] M. Yamanari et al., "Full range polarization-sensitive swept-source optical coherence tomography at 1-um with polarization modulation and BM-mode scan."

Thursday, January 21, 2010

One-Micrometer Adaptive Optics for Scanning Laser Ophthalmoscope

Our colleague Kazuhiro Kurokawa recently reported an adaptive optics scanning laser ophthalmoscope (AO-SLO) with a one-micrometer probe beam. This AO-SLO is the world first demonstration of an adaptive-optics based high-resolution retinal imager with this wavelength band. The mosaic of cone photoreceptors and the flow of blood cells of in vivo human eyes were visualized. The details were published in Optics Express.

Thursday, January 14, 2010

Full-Range Doppler OCT with High Dynamic Range

Franck Jaillon from COG in the University of Tsukuba demonstrated a new full range spectral domain optical coherence tomography (OCT), so called parabolic BM-scan method. This method is a variation of full-range OCT based BM-scan method, but possesses higher tolerance to the sample motion and higher dynamic range of Doppler measurement. In this paper, in vivo investigation of human eye was performed, and it was found that this parabolic BM-scan method is useful for office-based in vivo measurements. The details of this method were published in Optics Express.

Wednesday, January 13, 2010

Yasuno became associate editor of Optics Express

Our colleague Yoshiaki Yasuno became an associate editor of Optics Express. Optics Express is organized by Optical Society of America, and is one of the highest impact journals in the field of optics. Yasuno edits papers mainly of biomedical optics.

Friday, January 8, 2010

Generalized Jones Matrix OCT

Shuichi Makita and his colleagues in COG recently reported the generalization of Jones matrix optical coherence tomography (Jones OCT) in Optics Express. In this paper, we generalized theoretical model of Jones OCT which provides us not only phase retardation tomography but local birefringence tomography of biological and medical samples. The noise property of this generalized Jones OCT is also carefully analyzed. This method was applied to visualize the details of an anterior eye chamber, and successfully contrast a trabecular meshwork. The details are described in the following paper.

Citation: S. Makita, M. Yamanari, and Y. Yasuno, "Generalized Jones matrix optical coherence tomography: performance and local birefringence imaging," Opt. Express 18, 854-876 (2010).

Thursday, January 7, 2010

Investigation of Choroidal Thickness

Our collaborator Yasushi Ikuno (Osaka University Hospital) investigated the choroidal thickness of healthy Japanese. The chorid is one of the tissues in the eye ant it locates beneath the retina, and which had not been possible to be clearly visualized by OCT. He investigated the choroid by using a brand new high-penetration OCT made by our group (COG, Tsukuba). After the examination of 86 eyes, he found that the choroidal thickness varies around its position, and is associated the refractive error of the eye, axial eye length, and the age of the subject. The details are reported in Investigative Ophthalmology and Visual Science (IOVS, a journal of association for research in vision and ophthalmology).
>> Request reprint via e-mail (please indicate the following citation in the e-mail).

Citation: Y. Ikuno, K. Kawaguchi, T. Nouchi, and Y. Yasuno, "Choroidal thickness in healthy Japanese Subjects," Invest. Ophthalmol. Vis. Sci., e-first publication.

Birefringence Imaging of Necrotizing Scleritis

Our colleagues Masahiro Miura published a case report of necrotizing scleritis, which is an inflammation disease of sclera. The anterior eye of a patient was scanned by our anterior eye segment polarization sensitive optical coherence tomography prototype (AS-PS-OCT). The tissue selective imaging ability of AS-PS-OCT visualized the abnormal thinning of the eye. The details were published in Ophthalmic Surgery, Lasers and Imaging.
>> Request reprint via e-mail (please indicate the following citation in the e-mail.)

Citation: M. Miura, M. Yamanari, T. Iwasaki, M. Itoh, T. Yatagai, and Y. Yasuno, "Polarization-sensitive optical coherence tomography of necrotizing scleritis," Ophthalmic Surg. Lasers Imaging 40, 607-610 (2009).