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T. E. Fabritius, S. Makita, R. Myllylä, M. Miura, Y. Yasuno; High-Penetration, High-Resolution and Wide Range Volumetric Imaging of the Human Retina and Choroid With Spectral-Domain Optical Coherence Tomography at 1-µm Band. Invest. Ophthalmol. Vis. Sci. 2008;49(13):4235.
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© ARVO (1962-2015); The Authors (2016-present)
To demonstrate the high-speed, high-penetration, and high-resolution imaging of human retina and choroid by using 1 µm band spectral-domain optical coherence tomography (SD-OCT).
The current standard OCT uses the probe wavelength of 830 nm. Although, this wavelength provides high-resolution and high-contrast tomography of retina, the contrasts of choroid and the pathologies beneath retinal pigment epithelium were not sufficiently high. New OCT systems with a probe wavelength of 1 µm have been demonstrated for the high-contrast imaging of the deep posterior eye. However, none of them has the sufficiently high depth resolution, wide measurement range, nor fast measurement speed to enable clinically practical volumetric tomography. In this study we build SD-OCT at 1 µm wavelength with all of these features. The depth resolution was measured to be ~7 µm in tissue. The measurement speed was upto 38,000 axial scans/sec, which results in the volumetric measurement time of 3.4 sec with 1024 x 128 axial scans. Custom-made optical and numerical algorithm successfully removed the mirror image of the SD-OCT; hence the maximum depth range of our SD-OCT is 5.7 mm with 1024 depth image pixels.Two eyes of 2 patients of exudative age-related macular degeneration (ARMD) and 3 eyes of 3 normal subjects were examined by this OCT in its macular area. The optic nerve head of the normal subjects were also examined to evaluate the benefit of wide measurement range of this OCT. The patients were also scanned by standard SD-OCT with 830 nm probe beam for the qualitative comparison.
Three-dimensional retinal and choroidal tomographies were measured. The choroid showed very high contrast in 1-µm SD-OCT in comparison to that in 830 nm SD-OCT. The high-resolution properties of this SD-OCT visualized clear retinal layered structures including the details of the RPE-complex. The retinal abnormalities beneath choroidal neovascularization of the ARMD patients were visualized with high contrast. The wide range and high-penetration features of this SD-OCT enabled the imaging of the entire structure of ONH with deep cupping and the imaging of lamina cribrosa.
It was found that the high-speed, high-resolution 1-µm SD-OCT visualized clinically significant pathologies of ARMD and important features of normal subjects with high contrasts.
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