Open Access

This project, which is funded by the German Federal Ministry of Education and Research, attempts to improve the accessibility of diagnostic instruments for glaucoma screening. The presented approach aims to realize real-time near-infrared video fundus imaging that enables the use of targeted fixation stimuli to ensure continuous imaging. The integration of near-infrared illumination with a wavelength of 780 nm not only avoids pupil constriction, but also enables mesopic imaging in darkened ambient light, ensuring optimal visualization of the retinal structure. This innovative system achieves nearly reflection-free imaging through polarized illumination with polarization-dependent beam paths. Its primary aim is to capture extensive fundus areas to facilitate correlations with linear optical coherence tomography (LOCT) measurements. In the future, the fundus setup will be integrated into the LOCT setup. In this research project, the primary aim is to generate images of the optic nerve, but it is also possible to carry out examinations of the macula. Unlike from traditional fundus cameras, this system has a controllable screen for generating individual fixation stimuli, which creates continuous eye movements and enables controlled imaging. The main objective is to capture large fundus areas and track eye positions to combine this information with the LOCT measurements A-scan positions, which enables the creation of B-scans with irregular geometries. This approach replaces the need for complex scanning systems by leveraging natural eye movements. The approach can thus be used to detect retinal pathologies in a different way and could therefore be used for more comprehensive diagnostic and scientific applications.

For most classes of chains, it is known if these contain locks, but especially for fixed-angle equilateral equiangular obtuse open polygonal chains in 3D, which can be used to model protein backbones, this is unknown. Fixed-angle equilateral equiangular obtuse closed and open polygonal chains can be used to model polymers. For these, it is clear, that locks based on knots exist, but not which chains are generally locked. We therefore examine both open and closed fixed-angle equilateral equiangular obtuse chains. For this purpose, those chains are divided into various subgroups and, depending on the subgroup, other aspects are investigated to show locks. Techniques from knot theory, graph theory, and specifically robot arm reachability and motion planning are combined. Algorithms are developed to create chains in desired configurations and to study them. It is shown why all fixed-angle equilateral equiangular obtuse closed chains are expected to be locked or in rare cases rigid and non-locked, but never non-locked and non-rigid. For fixed-angle equilateral equiangular obtuse open chains it is shown why it is expected that there are open chains that are locked and that the smallest locked open chain has 𝑛=7.