Failure in mucociliary clearance is responsible for severe diseases like cystic fibroses, primary ciliary dyskinesia or asthma. Visualizing the mucous transport in-vivo will help to understanding transport mechanisms as well as developing and validating new therapeutic intervention. However, in-vivo imaging is complicated by the need of high spatial and temporal resolution. Recently, we developed microscopy optical coherence tomography (mOCT) for non-invasive imaging of the liquid-air interface in intact murine trachea from its outside.
Whereas axial resolution of 1.5 µm is achieved by the spectral width of supercontinuum light source, lateral resolution is limited by aberrations caused by the cylindric shape of the trachea and optical inhomogenities of the tissue. Therefore, we extended our mOCT by a deformable mirror for compensation of the probe induced aberrations. Instead of using a wavefront sensor for measuring aberrations, we harnessed optimization of the image quality to determine the correction parameter.
With the aberration corrected mOCT ciliary function and mucus transport was measured in wild type and βENaC overexpressing mice, which served as a model for cystic fibrosis.
A Hartmann-Shack wavefront sensor (HSWS) has been proven to be a reliable tool for the quantitative analysis of human ocular aberrations. In an active adaptive optics (AO) system, it has the role to monitor wave aberrations. To ensure the exclusive retrieval of Zernike coefficients for the measured ocular wavefronts, we first nullify the AO system's aberrations. This is of particular importance in our setup with a twisted-nematic (TN) liquid-crystal-on-silicon (LCoS) chip as the wavefront manipulator due to its strong unwanted zero-order diffractive beam. We characterize the AO system's performance-before and after ocular corrections-by means of different parameters, including experimental and simulated point spread functions (PSFs). An iterative closed-loop algorithm reduces the residual wavefront error to typical values of 0.1 µm. This system constitutes a wavefront corrector that can possibly be used for high resolution retinal imaging purposes or for visual psychophysical experiments.
We describe a bench top system for digital scanning laser ophthalmoscopy. This system is used for both regular patient screening and experimental imaging studies. The complete set- up is assembled from a number of modules (e.g. launching, detection, scanning, focusing unit) which may be altered readily to offer a high degree of flexibility in the imaging conditions. Both the launching and the detection unit can be used in a simultaneous, multiple channel configuration. This allows the acquisition of true color and false color images of the back of the eye. In particular, the use of infrared lines permits the investigation of deeper retinal structures. Digital image processing methods can then be used to generate differential images of frames taken with different wavelengths, such as red and infrared. Furthermore, the separate detection channels can also be used to obtain recordings in other imaging modes, such as tightly confocal, loosely confocal, indirect or polarization dependent contrast. We discuss the merits and problems of different imaging modes. Cases are presented where the differential imaging shows clear advantages over the standard (monochromatic) confocal method in the perceptibility of deeper laying structures (choriod).
The scanning laser ophthalmoscope (SLO) is a modern tool which is now widely used to image the fundus of the eye, particularly for assessment of the optic nerve head. We describe a modified SLO capable of producing stereo pairs of the optic disk in real time. A pair of toggling mirrors is used to switch between entry positions of the scanned laser beam into the pupil of the eye thereby creating a stereo base for capturing the two different views required for the pair. Our laboratory prototype is constructed from reflective optics only in the bi-directional part of the beam path, including the focusing and beam shaping unit. Thus, we avoid unwanted back reflections and chromatic aberrations. Light from different laser sources (458 to 1100 nm) can be launched into the SLO, also simultaneously. Collimated beams in beam splitting locations allow for easy modifications. Imaging in fluorescence mode or polarization dependent imaging is also possible. High quality multi-wavelengths stereo pairs of both model and real optic disks were obtained. a lateral resolution of up to 6 micrometer and an axial resolution of up to 65 micrometer was established.
The light intensity distribution in detection planes of laser scanning microscopes contains more information on the object than that which is obtained from the detection of the intensity on the optical axis with ordinary confocal microscopes. We look for simple and fast algorithms to use this additional information for the improvement (e.g., for more precise measurements of positions of edges) of confocal images. Characteristic properties of intensity distribution curves like positions and heights of side lobes are obtained and its values are used for mathematical or logical operations. Quantities resulting from those procedures can show a more sensitive behavior than the usual confocal signal. In this way these quantities are suitable to act as additional parameters in the image processing of confocal images. The example of the measurement of the position of a slit is explained in detail. Some experimental aspects are discussed and an outlook on the effect of defocus is given.
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.