Shuichi Makita

Clinical application of high-contrast three-dimensional imaging of the retina, choroid, and optic nerve with three-dimensional Fourier domain optical coherence tomography

We present three dimensional (3D) imaging of macular diseases and glaucoma with high speed, Fourier domain optical coherence tomography (FD-OCT). Our FD-OCT system allows video rate cross-sectional imaging with 98 dB sensitivity and 4.3 μm depth-resolution in tissue. This performance results in high contrast sectional images that enhance visualization of fine retinal layers including external limiting membrane and of deep structure such as the choroid and optic nerve. Volume rendering of 3D OCT data set taken for 3.5 seconds provides realistic 3D images of macular, optic disc and their pathologic changes. This manuscript will show the methods for three dimensional FD-OCT including a raster scanning protocol for volume rendering and cancellation of the motion artifact of eye balls, and the application of the high contrast three dimensional OCT imaging to macular diseases and glaucoma in clinical examination.

Simultaneous tissue birefringence and deformation measurement by polarization sensitive optical coherence elastography with active compression (Conference Presentation)

Polarization sensitive optical coherence tomography (PS-OCT) measures tissue birefringence, while optical coherence elastography (OCE) reveals the mechanical property of the tissue. Since both birefringence and mechanical properties are associated with tissue microstructures such as collagen, simultaneous PS-OCT and OCE measurement will provide useful insight for the tissue microstructures. In this paper, we present a combined PS-OCT and OCE technique.nThe PS-OCT is based on Jones matrix OCT theory. It measures a tomography of Jones matrix. Birefringence tomography is then deduced from the Jones matrix. The OCE is obtained with active tissue compression. The tissue compression was performed by a ring piezoelectric (PZT) actuator installed in front of an objective. A glass slip is attached at the fore-end of the PZT to push a tissue. Multiple cross sections were synchronously measured through the glass slip with gradual tissue compression (0 – 12 µm at maximum). The raw Jones matrix tomography consists of 4 complex-valued OCT images. Two of the 4 images (two orthogonal detection polarization images of a single input polarization) are processed by a correlation based tissue displacement-and-deformation analysis method [Kurokawa et al., Opt. Lett., 2153-, 2015]. It provides polarization artifact free cross-sectional maps of (1) axial displacement, (2) lateral displacement, and (3) microstructural deformation. nThe method was evaluated by measuring porcine muscle tissues. It was observed that the muscle has subdomains with different deformation properties. In addition, the cross-sectional deformation map distinctively visualized that the muscle and adipose has significantly different deformation properties. Different muscle samples shows different birefringence strength.

Objective evaluation of choroidal melanin contents with polarization-sensitive optical coherence tomography

We non-invasively evaluated choroidal melanin contents in human eyes with PS-OCT. We calculated the percentage area of low DOPU in the choroidal interstitial stroma for Vogt-Koyanagi- Harada disease with sunset glow fundus, without sunset glow fundus, control group and tessellated fundus with high myopia. The mean percentage area of low DOPU in the sunset group was significantly lower than the other groups. PS-OCT provides an in vivo objective evaluation of choroidal melanin loss in vivo human eyes.