Enhanced visualization of tissue contrast and morphological boundaries is demonstrated by analyzing OCT volume data
in two distinct wavelength regions. The extension of this so-called simultaneous dual-band method to three dimensions is
realized by a custom-built 3D spectral domain OCT system imaging in the 800 und 1200 nm wavelength domain. Color
representations of the spectral differences of high resolution OCT volume data significantly simplify the discrimination
of different tissue structures beyond the capabilities of cross-sectional spectroscopic OCT approaches.
KEYWORDS: Optical coherence tomography, Eye, Cornea, Eye models, In vitro testing, Systems modeling, Pathogens, 3D modeling, Animal model studies, Scattering
Three dimensional optical coherence tomography (OCT) is introduced as a valuable tool to analyze the pathogenesis of
corneal diseases. Here, OCT in combination with a novel in vitro model for the dry eye syndrome enables an improved
understanding of the underlying damaging process of the ocular surface. En-face OCT projections indicate a deep
structural damage of the epithelium and anterior stroma by osmotic forces.
We present a fiber-based spectral-domain optical coherence tomography system, measuring simultaneously at 740 nm
and 1300 nm central wavelengths. Real-time imaging is demonstrated with axial resolutions <3 μm and <5 μm,
respectively. This technique allows for in vivo functional OCT imaging with high spatial resolution and outstanding
spectroscopic imaging contrast.
An off-the-shelf turn-key supercontinuum light source based on a passively mode-locked fiber laser, a fiber amplifier and
a highly nonlinear fiber is evaluated for its application in ultrahigh resolution optical coherence tomography (OCT). Two
spectral bands - one red shifted and one blue shifted in reference to the wavelength of the fiber laser - are employed
as low coherence sources in OCT. Usable spectral bandwidths exceed 300 nm centered either at 790 or 1340 nm, with
corresponding coherence lengths of 1.2 and 2.6 μm, respectively. Optimization of the spectrum for simultaneous imaging
at both spectral bands results in spectral bandwidths exceeding 200 nm for each band after filtering. A free-space
OCT setup supporting the full spectral bandwidth is introduced which allows for ultrahigh resolution OCT imaging using
both spectral bands simultaneously. Axial free space resolutions were measured to be less than 2 and 4 μm at 840 and
1230 nm, respectively. This approach combines ultrahigh resolution obtained at 840 nm with large penetration depths at
1230 nm. Frequency compounding of the OCT images can be used for speckle reduction while extracting spatially resolved
spectroscopic features facilitates enhanced image contrast.
For chemical burns a considerable lack of methods exists for defining penetration kinetics and effects of decontamination
within biological structures. We demonstrate that time-resolved high-resolution optical coherence tomography can close
this gap by monitoring changes in scattering properties and thicknesses of rabbit cornea ex vivo after topical application
of different corrosives. Modifications in the corneal microstructure due to direct chemical interaction or changes in the
hydration state as a result of osmotic imbalance compromise the corneal transparency. The associated increase in light
scattering intensity within the cornea is observed with high spatial and temporal resolution. Parameters affecting the severity
of pathophysiological damage like diffusion velocity, depth of penetration, resistance of barriers, and effectiveness of
emergency treatment procedures are obtained. This study demonstrates the potential of high-resolution OCT for the visualization
and direct non-invasive measurement of specific interaction of chemicals with the eye, exemplified on hydrofluoric
acid burn.
The use of high-resolution optical coherence tomography (OCT) to visualize penetration kinetics during the initial phase of chemical eye burns is evaluated. The changes in scattering properties and thickness of rabbit cornea ex vivo were monitored after topical application of different corrosives by time-resolved OCT imaging. Eye burn causes changes in the corneal microstructure due to chemical interaction or change in the hydration state as a result of osmotic imbalance. These changes compromise the corneal transparency. The associated increase in light scattering within the cornea is observed with high spatial and temporal resolution. Parameters affecting the severity of pathophysiological damage associated with chemical eye burns like diffusion velocity and depth of penetration are obtained. We demonstrate the potential of high-resolution OCT for the visualization and direct noninvasive measurement of specific interaction of chemicals with the eye. This work opens new horizons in clinical evaluation of chemical eye burns, eye irritation testing, and product testing for chemical and pharmacological products.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.