This paper documents the design, implementation and evaluation of the Unfolding Space Glove—an open source sensory substitution device. It transmits the relative position and distance of nearby objects as vibratory stimuli to the back of the hand and thus enables blind people to haptically explore the depth of their surrounding space, assisting with navigation tasks such as object recognition and wayfinding. The prototype requires no external hardware, is highly portable, operates in all lighting conditions, and provides continuous and immediate feedback—all while being visually unobtrusive. Both blind (n = 8) and blindfolded sighted participants (n = 6) completed structured training and obstacle courses with both the prototype and a white long cane to allow performance comparisons to be drawn between them. The subjects quickly learned how to use the glove and successfully completed all of the trials, though still being slower with it than with the cane. Qualitative interviews revealed a high level of usability and user experience. Overall, the results indicate the general processability of spatial information through sensory substitution using haptic, vibrotactile interfaces. Further research would be required to evaluate the prototype’s capabilities after extensive training and to derive a fully functional navigation aid from its features.

Thermal ablation for Barrett’s oesophagus has widely been established in gastrointestinal endoscopy during the last decade. The mainly used methods of radiofrequency ablation (RFA) and argon-plasma coagulation (APC) carry a relevant risk of stricture formation of up to 5–15%. Newer ablation techniques that are able to overcome this disadvantage would therefore be desirable. The aim of the present study was to compare the depth of tissue injury of the new method of Hybrid-APC versus standard APC within a randomized study in a porcine oesophagus model. Using a total of eight explanted pig oesophagi, 48 oesophageal areas were ablated either by standard or Hybrid-APC (APC with prior submucosal fluid injection) using power settings of 50 and 70 W. The depth of tissue injury to the oesophageal wall was analysed macroscopically and histopathologically. Using 50 W, mean coagulation depth was 937 ± 469 µm during standard APC, and 477 ± 271 µm during Hybrid-APC (p = 0.064). Using 70 W, coagulation depth was 1096 ± 320 µm (standard APC) and 468 ± 136 µm (Hybrid-APC; p = 0.003). During all settings, damage to the muscularis mucosae was observed. Using standard APC, damage to the submucosal layer was observed in 4/6 (50 W) and 6/6 cases (70 W). During Hybrid-APC, coagulation of the submucosal layer occurred in 2/6 (50 W) and 1/6 cases (70 W). The proper muscle layer was only damaged during conventional APC (50 W: 1/6; 70 W: 3/6). Ex-vivo animal study with limited number of cases. Hybrid-APC reduces coagulation depth by half in comparison with standard APC, with no thermal injury to the proper muscle layer. It may therefore lead to a lower rate of stricture formation during clinical application.

In this study, we investigate to what degree augmented reality technology can be used to create and evaluate a visual-to-auditory sensory substitution device to improve the performance of blind persons in navigation and recognition tasks. A sensory substitution algorithm that translates 3D visual information into audio feedback was designed. This algorithm was integrated in an augmented reality based mobile phone application. Using the mobile device as sensory substitution device, a study with blind participants (n = 7) was performed. The participants navigated through pseudo-randomized obstacle courses using either the sensory substitution device, a white cane or a combination of both. In a second task, virtual 3D objects and structures had to be identified by the participants using the same sensory substitution device. The realized application for mobile devices enabled participants to complete the navigation and object recognition tasks in an experimental environment already within the first trials without previous training. This demonstrates the general feasibility and low entry barrier of the designed sensory substitution algorithm. In direct comparison to the white cane, within the study duration of ten hours the sensory substitution device did not offer a statistically significant improvement in navigation.

In this work, we explore the potential and limitations of simulating gaze-contingent tunnel vision conditions using Virtual Reality (VR) with built-in eye tracking technology. This approach promises an easy and accessible way of expanding study populations and test groups for visual training, visual aids, or accessibility evaluations. However, it is crucial to assess the validity and reliability of simulating these types of visual impairments and evaluate the extend to which participants with simulated tunnel vision can represent real patients. Two age-matched participant groups were acquired: The first group (n = 8, aged 20–60, average 49.1 ± 13.2) consisted of patients diagnosed with Retinitis pigmentosa (RP). The second group (n = 8, aged 27–59, average 46.5 ± 10.8) consisted of visually healthy participants with simulated tunnel vision. Both groups carried out different visual tasks in a virtual environment for 30 min per day over the course of four weeks. Task performances as well as gaze characteristics were evaluated in both groups over the course of the study. Using the ’two one-sided tests for equivalence’ method, the two groups were found to perform similar in all three visual tasks. Significant differences between groups were found in different aspects of their gaze behavior, though most of these aspects seem to converge over time. Our study evaluates the potential and limitations of using Virtual Reality technology to simulate the effects of tunnel vision within controlled virtual environments. We find that the simulation accurately represents performance of RP patients in the context of group averages, but fails to fully replicate effects on gaze behavior.

People living with a degenerative retinal disease such as retinitis pigmentosa are oftentimes faced with difficulties navigating in crowded places and avoiding obstacles due to their severely limited field of view. The study aimed to assess the potential of different patterns of eye movement (scanning patterns) to (i) increase the effective area of perception of participants with simulated retinitis pigmentosa scotoma and (ii) maintain or improve performance in visual tasks. Using a virtual reality headset with eye tracking, we simulated tunnel vision of 20° in diameter in visually healthy participants (n = 9). Employing this setup, we investigated how different scanning patterns influence the dynamic field of view—the average area over time covered by the field of view—of the participants in an obstacle avoidance task and in a search task. One of the two tested scanning patterns showed a significant improvement in both dynamic field of view (navigation 11%, search 7%) and collision avoidance (33%) when compared to trials without the suggested scanning pattern. However, participants took significantly longer (31%) to finish the navigation task when applying this scanning pattern. No significant improvements in search task performance were found when applying scanning patterns.

Ein- oder beidseitige Okulomotoriusparesen machen gut ein Drittel der die Okulomotorik betreffenden Hirnnervenparesen aus. Aufgrund des ausgedehnten Kernkomplexes und Versorgungsgebiets treten NIII-Paresen häufiger inkomplett als komplett mit Ausfall der 4 versorgten äußeren Augenmuskeln, des M. levator palpebrae und der beiden versorgten inneren Augenmuskeln auf. Nach Ausschöpfen der konservativen Therapiemöglichkeiten und gegebenenfalls Abwarten einer Spontanremission kann eine operative Therapie zur Beseitigung der Diplopie bzw. Schaffung eines zentralen Fusionsblickfelds, zur Reduktion einer Kopfzwangshaltung oder zur Verbesserung des äußeren Erscheinungsbilds angezeigt sein. Je nach Befund können diese Ziele nicht immer vollständig und mit einer Operation erreicht werden. Einfache schwächende und stärkende Eingriffe aus dem Standardrepertoire der Augenmuskelchirurgie erbringen bei ausgeprägten Motilitätseinschränkungen im Rahmen einer Okulomotoriusparese oft keine ausreichende Stellungskorrektur. Transponierende Augenmuskeloperationen sind in die Differenzialtherapie miteinzubeziehen. Die bei der individuellen Indikationsstellung zu berücksichtigenden Parameter wie Paresemuster, Binokularprognose, mögliche Fehlinnervationen und eventuell begleitende Trochlearisparese werden grundsätzlich und anhand von Fallbeispielen diskutiert. Uni- or bilateral third nerve palsies account for about one third of cranial nerve palsies affecting ocular motility. Due to the large nuclear complex of the third nerve and due to the multiple effector muscles of the third nerve, incomplete palsies are common. When conservative treatment is insufficient and a potential remission did not occur, surgical intervention on the extraocular muscles may be indicated to reduce diplopia, establish a field of binocular single vision or relieve annoying head postures or improve the patient’s appearance. Standard procedures in strabismus surgery such as simple recessions or strengthening procedures often do not yield permanent effects under the conditions of third nerve palsies so that transposition procedures may be required. Special considerations in individual indications, e. g., concerning binocular prognosis, possible misinnervation and potential accompanying fourth nerve palsy are discussed in general and illustrated with case reports.