Ophthalmologie
January 2024
Background: The Professional Association of Ophthalmologists (BVA) estimates that at least 100,000s of traffic accidents with 10,000s of injuries and fatalities are caused by known and unknown visual disorders on German roads every year. Until now, however, the police have not had the opportunity to check for potential visual disorders on the spot in cases of conspicuous driving. In a pilot project of the police with the Eye Hospital of the Hannover Medical School (MHH), the aim was for the first time to extend the existing tests of the police by adapted "car-side" vision tests.
View Article and Find Full Text PDFSensors (Basel)
December 2020
Optical coherence tomography (OCT) enables three-dimensional imaging with resolution on the micrometer scale. The technique relies on the time-of-flight gated detection of light scattered from a sample and has received enormous interest in applications as versatile as non-destructive testing, metrology and non-invasive medical diagnostics. However, in strongly scattering media such as biological tissue, the penetration depth and imaging resolution are limited.
View Article and Find Full Text PDFRecently the acquisition of the time-resolved reflection matrix was demonstrated based on spectral domain optical coherence tomography. In principle, the matrix describes the linear dependence of the OCT signal received from different depths on the field which is incident to the scattering sample. Knowledge of the matrix, hence, enables beam shaping to selectively enhance the received signal, for example to increase the penetration depth when imaging turbid media.
View Article and Find Full Text PDFSpectral domain optical coherence tomography (SD-OCT) is a highly versatile method which allows for three dimensional optical imaging in scattering media. A number of recent publications demonstrated the technique to benefit from structured illumination and beam shaping approaches, e.g.
View Article and Find Full Text PDFIn this article, we present a simple and intuitive approach to create a handheld optoacoustic setup for near field measurements. A single piezoelectric transducer glued in between two sheets of polymethyl methacrylate (PMMA) facilitates nearfield depth profiling of layered media. The detector electrodes are made of indium tin oxide (ITO) which is both electrically conducting as well as optically transparent, enabling an on-axis illumination through the detector.
View Article and Find Full Text PDFWe propose a compact setup for wavefront manipulation in spectral domain optical coherence tomography (OCT). The system can easily be implemented into existing free-space OCT setups through modification of the source path only. We demonstrate complex-valued OCT signal acquisition based on phase shifting combined with iterative optical wavefront shaping, which locally enhances the OCT signal acquired from within a scattering sample.
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