Wednesday, September 16, 2009

Tissue Discrimination Imaging of Anterior Eye

Our colleague Arata Miyazawa reported a new imaging methodology which used polarization sensitive optical coherence tomography (PS-OCT) and a newly developed algorithm to discriminate tissues based on their optical properties. This algorithm uses three optical properties obtained by PS-OCT including scattering intensity, signal extinction coefficient along depth, and local birefringence, and discriminates tissues based on these properties. By using this algorithm, five tissue types of an anterior eye including trabecular meshwork, conjunctiva, sclera, cornea and uvea were successfully discriminated. The details was published in Optics Express.

Citation: A. Miyazawa, M. Yamanari, S. Makita, M. Miura, K. Kawana, K. Iwaya, H. Goto, and Y. Yasuno, "Tissue discrimination in anterior eye using three optical parameters obtained by polarization sensitive optical coherence tomography, " Opt. Express 17, 17426-17440 (2009).

Friday, September 11, 2009

Ocular Biometry by 3D-OCT

Our collaborator Shinichi Fukuda investigated the utility of 3D corneal and anterior eye segment optical coherence tomography (3D-CAS-OCT) for ocular biometry. The ocular biometry is a method to extract numerical parameters from an eye, which represent the functions and integrity of the eye, e.g. a central corneal thickness (CCT) or an anterior eye chamber depth (ACD).

He examined 40 eyes of 40 normal subjects by 3D-CAS-OCT, Scheimpflug camera, scanning-slit topography and ultrasonic pachymetry, and obtained CCT, ACD and other parameters. This study indicated 3D-CAS-OCT was usable for ocular biometry.

This study has been reported on a journal Ophthalmology. The paper and abstract is available on the following locations.

>> Journal web site
>> Request reprint via e-mail (please indicate the following citation in the e-mail.)

Citation: S. Fukuda, K. Kawana, Y. Yasuno and T. Oshika, "Anterior ocular biometry using 3-dimensional optical coherence tomography," Ophthalmology 116, 882-889 (2009).

3D Investigation of Glaucoma Surgery

Keisuke Kawana has reported 3D tomographic investigation of trabeculectomy blebs. The bleb is an artificial structure created on the anterior eye by a surgery "trabeculectomy" which is for the treatment of glaucoma. He employed 3D swept-source OCT for this investigation. Internal outflow channels and scleral flaps were successfully visualized.

This report has been published in Opthalmology, and available from the following links.
>> Request reprint via e-mail. (Please copy and past the following citation.)

Citation: K. Kawana, T. Kiuchi, Y. Yasuno and T. Oshika, "Evaluation of trabeculectomy blebs using 3-dimensional cornea and anterior segment optical coherence tomography," Ophthalmology 116, 848-855 (2009).

Monday, September 7, 2009

Publication: OCT guided surgery of cornea

Hideki Mori recently published a paper of 3D OCT guided phototherapeutic keratectomy (PTK) for the treatment of granular corneal dystrophy. In this paper, he demonstrated a simulation of laser surgery of corneal dystrophy based on 3D OCT volume. This simulation was compared to the result of real PTK surgery and they showed a good agreement.

(via e-mail. Please indicate the citation).

Citation: H. Mori, M. Miura, T. Iwasaki, H. Goto, Y. Sakurai, Y. Watanabe and Y. Yasuno, "Three-dimensional optical coherence tomography-guided phototherapeutic keratectomy for granular corneal dystrophy, " Cornea 28, 944-947 (2009).

Tuesday, September 1, 2009

New Publication: Dermal Birefringence and Skin Surface

Shingo Sakai recently published a paper "Relationship Between Dermal Birefringence and the Skin Surface Roughness of Photoaged Human Skin" in Journal of Biomedical Optics. In this paper, he showed a significant correlation between the birefringence of the upper dermal region of human skin and its surface roughness. This result suggests that solar elastosis is a major factor for the progress of wrinkles.
This paper is available on the website of Journal of Biomedical Optics.

Citation: S. Sakai, N. Nakagawa, M. Yamanari, A. Miyazawa, Y. Yasuno and M. Matsumoto, "Relationship between Dermal Birefringence and the Skin Surface Roughness of Photoaged Human Skin," J. Biomed. Opt. 14, 044032 (2009).

Monday, August 31, 2009

New Publication: Segmentation of Retinal Pigment Epithelium

Tapio Fabritius recently published a paper which describes an automated and fast algorithm to segment retinal pigment epithelium (RPE) by using the intensity based OCT images. This algorithm is using an itteration loop to connect the segmented locations of RPE of each B-scan, and provide smooth en-face map of RPE position. It was also proven that this algorithm works well with pathologic cases.

This paper is freely available on Optics Express website.

Citation: T. Fabritius, S. Makita, M. Miura, R. Myllyla, and Y. Yasuno, "Automated segmentation of the macula by optical coherence tomography," Opt. Express 17, 15659-15669 (2009).

Tuesday, July 14, 2009

New publication: 1-um polarization-sensitive SS-OCT

Our new paper about 1-um polarization-sensitive SS-OCT was published in Optics Express. Phase retardation images of sclera and lamina cribrosa in the posterior eye were visualized at 1-um wavelength for the first time. We described how the system sensitivity was optimized and how the polarization-insensitive image was important for the imaging of birefringent tissues.

The paper is available with open access in Optics Express.

Citation: Masahiro Yamanari, Yiheng Lim, Shuichi Makita, and Yoshiaki Yasuno, "Visualization of phase retardation of deep posterior eye by polarization-sensitive swept-source optical coherence tomography with 1-µm probe," Opt. Express 17, 12385-12396 (2009)

Thursday, June 11, 2009

SPIE Newsroom: Multifunctional Anterior OCT

An article of our multifunctional anterior optical coherence tomography is now available on SPIE newsroom. This article for general readers may give you a quick overview of cutting-edge anterior OCT!


Our Ophthalmologist receives PhD of Engineering

I proudly announce that our aggressive ophthalmologist Dr. Masahiro Miura received PhD of Engineering, his second PhD,s from University of Tsukuba. The subject of his PhD was ophthalmic polarimetries in ophthalmology, which includes polarimetric scanning laser ophthalmoscope and polarization sensitive optical coherence tomography. His PhD thesis "Imaging Polarimetry of Human Eye" is available on the following link.


Friday, March 13, 2009

New publication: 3D polarization sensitive OCT of glaucoma surgery

Our new paper is now published in Optics Express. This paper presents a case series of glaucoma surgeries measured by our three-dimensional polarization sensitive optical coherence tomography (3-D PS-OCT). Since this paper is an interactive scientific publication (SIP), full 3-D PS-OCT data sets of cases is downloadable in addition to conventional static picture-figures. You can download the datasets and can write your own signal processing software.

The manuscript is freely downloadable from Optics Express web-site.

Citation: Y. Yasuno, M. Yamanari, K. Kawana, T. Oshika, and M. Miura, "Investigation of post-glaucoma-surgery structures by three-dimensional and polarization sensitive anterior eye segment optical coherence tomography," Opt. Express 17, 3980-3996 (2009).

Joschi, Yoshiaki Yasuno

Wednesday, February 25, 2009

New Publication: Retinal Shadow Compensation in Retinal OCT

Our new paper was published in Journal of Biomedical Optics Letters (JBO). This paper describes a simple but effective numerical algorithm to remove shadowing artifacts caused by retinal vessels in an optical coherence tomography (OCT) image. The paper is published in an open access manner, and available on JBO web site.

Citation: T. Fabritius, S. Makita, Y. Hong, R. Myllyla and Y. Yasuno, "Automated retinal shadow compensation of optical coherence tomography images," J. Biomed. Opt. 14, 010503 (2009).

Monday, February 23, 2009

Kurokawa won Pascal Rol Award

Kazuhiro Kurokawa (Computational Optics Group in the University of Tsukuba) was chosen as the best presenter and received Pascal Rol Award at Photonics West in January, 2009.

Pascal Rol Award was established for the promotion of ophthalmic technologies in the memory of Pascal Rol (University Eye Clinic, Zurich). This Pascal Rol Award is given to the best presented ophthalmic engineer at Photonics West.

Kurokawa was the one who gained acceptance with his research "one-micrometer wavelength adaptive optics scanning laser opthalmoscope."


黒川氏がPascal Rol Award受賞

先月米国にて開催されたPhotonics Westにおいて黒川和博氏(Computational Optics Group in the University of Tsukuba)が2009年のPascal Rol Awardを受賞しました。
Pascal Rol Award賞は2000年に急逝した著名な眼科光学研究者であるPascal Olivier Rol(チューリッヒ眼科大学病院、マイアミ大学)の功績を称えて設立されたものであり、Photonics Westにおいて最も優れた研究を公表した眼科工学研究者一人に贈られます。
今回はマサチューセッツ工科大学、ウィーン医科大学等からの他のノミネートを抑えて黒川氏が研究成果「1μm帯域光を利用したレーザー走査検眼鏡」を認められての受賞となりました。Computational Optics Groupでは2007年の安野嘉晃氏に続き二度目の受賞となります。


Thursday, February 19, 2009

New Publication: Investigation of photo-aging by PS-OCT

A new paper was published by our project of polarization sensitive optical coherence tomography (PS-OCT) and skin investigation in Journal of Investigative Dermatology (JID). In this paper, we examined photo-aged skins of young and old subjects by PS-OCT and quantitatively analyzed the skin birefringence. In this study, we found that dermal birefringence of the cheek skin, which was well exposed by sun light, was significantly smaller in the old group than in the young group. On the other hand, the interior upper arm, which was normally exposed by sun light, showed no age-dependent difference.
     The abstract and the full article are available on the journal web site and PubMed.

Citation: S. Sakai, M. Yamanari, A. Miyazawa, M. Matsumoto, N. Nakagawa, T. Sugawara, K. Kawabata, T. yatagai, and Y. Yasuno, "In vivo three-dimensional birefringence analysis shows collagen differences between young and old photo-aged human skin," J. Inv. Dermatol. 128, 1641-1647 (2008).

Joschi, Yoshiaki Yasuno

Update of Publication: AMD and High-Penetration OCT

Original article is on August 13, 2008

The following our paper is now officially published in Investigative Ophthalmology and Visual Science (IOVS).

Y. Yasuno, M. Miura, K. Kawana, S. Makita, M. Sato, F. Okamoto, M. Yamanari, T. Iwasaki, T. Yatagai, and T. Oshika, "Visualization of Sub-retinal Pigment Epithelium Morphologies of Exudative Macular Diseases by High-Penetration Optical Coherence Tomography," Inv. Ophthalmol. Vis. Sci. 50, 405-513 (2009).

This paper demonstrates the application of new OCT with one-micrometer probe wavelength (high-penetration OCT; HP-OCT) to age-related macular degeneration. 14 eyes were involved in this study, and the clinical utility of HP-OCT was discussed. Preliminary results which suggest higher robustness of HP-OCT to cataract than standard OCT were also shown. The paper is available on the journal web site (IOVS).