The effectiveness and safety of proton radiation therapy for indications of the eye : a systematic review

BACKGROUND AND PURPOSE: : Proton radiation has been used for the treatment of uveal melanoma since 1975, but few studies have been conducted to assess its efficacy and safety. This paper aims to systematically review the effects and side effects of proton therapy for any indication of the eye. MATERIAL AND METHODS: : A range of databases were searched from inception to 2007. All studies that included at least ten patients and that assessed the efficacy or safety of proton therapy for any indication of the eye were included. RESULTS: : The search generated 2,385 references, of which 37 met the inclusion criteria. Five controlled trials, two comparative studies and 30 case series were found, most often reporting on uveal melanoma, choroidal melanoma and age-related macular degeneration (AMD). Methodological quality of these studies was poor. Studies were characterized by large differences in radiation techniques applied within the studies, and by variation in patient characteristics within and between studies. Results for uveal melanoma and choroidal melanoma suggest favorable survival, with, however, significant rates of side effects. Results for choroidal hemangioma and AMD did not reveal beneficial effects from proton radiation. CONCLUSION: : There is limited evidence on the effectiveness and safety of proton radiation due to the lack of well-designed and well-reported studies. There is a need to lift evidence on proton therapy to a higher level by performing dose-finding randomized controlled trials (RCTs), comparative studies of proton radiation versus standard given alternatives and prospective case studies enrolling only patients treated with up-to-date techniques, allowing extrapolation of results to similar patient groups.

[Eye complications in chronic juvenile arthritis]

BACKGROUND: The relationship between uveitis anterior in childhood and juvenile chronic arthritis (JCA, respectively JRA) has been known since 1950. In a review, the clinical picture of uveitis anterior, its prevalence, pathogenesis, prognosis and current therapy of ocular complications are presented. In addition, we will report our results of a clinical study. PATIENTS AND METHODS: In a cross-sectional study, 64 patients with juvenile chronic arthritis (JCA) had an ophthalmological screening for eye complications either from the disease itself or from the treatment. RESULTS: In 16% of the patients, an iridocyclitis was found, in one case acute, in 9 cases chronic. The cases of chronic uveitis anterior showed in 43% a combination with the classic risk factors (ANA-positive, oligoarticular, female). At the beginning of uveitis, the patients had a mean age of 81 months, at the beginning of JCA disease a mean age of 37 months. Four of 10 patients (= 40%) had eye complications from uveitis (cataract, posterior synechiae, glaucoma). Complications from therapy were found in 27%, mostly cataract as a complication of systemic and topical steroid treatment. Eighteen % had a visual acuity of 0.4 or less. CONCLUSIONS: Because of the often asymptomatic progression of chronic uveitis anterior, the risk of severe undetected eye complications is high. Therefore, an intensive interdisciplinary cooperation between rheumatologists, pediatrics and ophthalmologists is required.

Evaluation of Binocular Eye Trackers and Algorithms for 3D Gaze Interaction in Virtual Reality Environments

Tracking user’s visual attention is a fundamental aspect in novel human-computer interaction paradigms found in Virtual Reality. For example, multimodal interfaces or dialogue-based communications with virtual and real agents greatly benefit from the analysis of the user’s visual attention as a vital source for deictic references or turn-taking signals. Current approaches to determine visual attention rely primarily on monocular eye trackers. Hence they are restricted to the interpretation of two-dimensional fixations relative to a defined area of projection. The study presented in this article compares precision, accuracy and application performance of two binocular eye tracking devices. Two algorithms are compared which derive depth information as required for visual attention-based 3D interfaces. This information is further applied to an improved VR selection task in which a binocular eye tracker and an adaptive neural network algorithm is used during the disambiguation of partly occluded objects.

Eye-head coordination abnormalities in schizophrenia

Eye-movement abnormalities in schizophrenia are a well-established phenomenon that has been observed in many studies. In such studies, visual targets are usually presented in the center of the visual field, and the subject's head remains fixed. However, in every-day life, targets may also appear in the periphery. This study is among the first to investigate eye and head movements in schizophrenia by presenting targets in the periphery of the visual field.

Analysis of eye and head coordination in a visual peripheral recognition task

Coordinated eye and head movements simultaneously occur to scan the visual world for relevant targets. However, measuring both eye and head movements in experiments allowing natural head movements may be challenging. This paper provides an approach to study eye-head coordination: First, we demonstra- te the capabilities and limits of the eye-head tracking system used, and compare it to other technologies. Second, a beha- vioral task is introduced to invoke eye-head coordination. Third, a method is introduced to reconstruct signal loss in video- based oculography caused by cornea reflection artifacts in order to extend the tracking range. Finally, parameters of eye- head coordination are identified using EHCA (eye-head co- ordination analyzer), a MATLAB software which was developed to analyze eye-head shifts. To demonstrate the capabilities of the approach, a study with 11 healthy subjects was performed to investigate motion behavior. The approach presented here is discussed as an instrument to explore eye-head coordination, which may lead to further insights into attentional and motor symptoms of certain neurological or psychiatric diseases, e.g., schizophrenia.

Finale Fixationen, sportmotorische Leistung und eine Inhibitionshypothese. Mechanismen des "Quiet Eye"

Vielfach konnte in den letzten Jahren die Bedeutung einer langen letzten Fixation vor Bewegungsbeginn – des sogenannten "Quiet Eye" – für die sportmotorische Leistung aufgezeigt werden. Obgleich dieses Phänomens breit untersucht wurde, mangelt es bislang an einer zufriedenstellenden Erklärung. In diesem Beitrag werden daher aktuelle Erklärungsversuche diskutiert. Es zeigt sich, dass vorliegende Beiträge aus der Kognitions- und der ökologischen Psychologie konzeptuelle oder methodische Mängel aufweisen. Aus diesen Gründen wird – zunächst für Aufgaben mit hohen Präzisionsanforderungen – ein Inhibitionsmechanismus zur Erklärung des Quiet-Eye-Phänomens vorgeschlagen mit der zentralen Aussage, dass die Verarbeitung leistungsrelevanter Hinweisreize durch ein "ruhiges Auge" von Störungen abgeschirmt wird. Abschließend kann gezeigt werden, dass sich der vorgeschlagene Mechanismus mit der bestehenden Befundlage als kompatibel erweist und er die Ableitung weitergehender Vorhersagen erlaubt.

The "Quiet Eye" and Motor Performance: Task Demands Matter!

Evidence suggests that superior motor performance coincides with a longer duration of the last fixation before movement initiation, an observation called “quiet eye” (QE). Although the empirical findings over the last two decades underline the robustness of the phenomenon, little is known about its functional role in motor performance. Therefore, a novel paradigm is introduced, testing QE duration as an independent variable by experimentally manipulating the onset of the last fixation before movement unfolding. Furthermore, this paradigm is employed to investigate the functional mechanisms behind the QE phenomenon by manipulating the predictability of the target position and thereby the amount of information to be processed over the QE period. The results further support the assumption that QE affects motor performance, with experimentally prolonged QE durations increasing accuracy in a throwing task. However, it is only under a high information-processing load that a longer QE duration is beneficial for throwing performance. Therefore, the optimization of information processing, particularly in motor execution, turns out to be a promising candidate for explaining QE benefits on a functional level.

Zielinstruktionen, räumliche Quiet-Eye-Verankerung und Bewegungsparametrisierung: Hinweise auf einen Wirkmechanismus

Die motorikwissenschaftliche Befundlage zum sogenannten „Quiet Eye“ weist darauf hin, dass hohe sportmotorische Leistungen, insbesondere in Präzisionsaufgaben, mit einer langen finalen Fixation vor der Bewegungsentfaltung einhergehen. Ein Mechanismus, der diesen Zusammenhang aus einer kognitionspsychologischen Perspektive erklären könnte, ist die Optimierung von Informationsverarbeitungsprozessen der Bewegungsparametrisierung. Diese Annahme wurde durch eine experimentelle Manipulation von Zielinstruktionen in einer Ballwurfaufgabe untersucht. Zum einen zeigen die Ergebnisse, dass sich die räumliche Verankerung des Quiet Eye in Abhängigkeit der variierten Aufgabenziele verändert; zum anderen deuten die Befunde darauf hin, dass sich Veränderungen der Verankerung im Bewegungsresultat niederschlagen. Damit wird ein kognitiver Wirkmechanismus plausibilisiert, nach dem die Bewegungsgenauigkeit durch Zielinstruktion via räumliche Quiet-Eye-Verankerung bestimmt wird.