Estudo experimental do comportamento ocular em trabalhadores administrativos como um indicador de conforto visual em situação de risco de encadeamento

The daylight impact on the visual environment is fundamental on visual display terminal work (VDT). Visual performance and visual comfort should be considered for equal. The study (n=16) was performed at the experimental lighting laboratory. Office work with VDT was evaluated using STROOP task in two orientations: (with/without solar presence in the visual field). Our hypothesis states the existence of a relationship between ocular behavior and visual comfort of workers. An eye-tracker was employed in order to record the ocular gestural parameters: blinks, direction of gaze, eye aperture (Degree of eye?s openness) and pupil size, which were correlated with the vertical illuminance at the eye. Visual comfort was assessed with Glare Sensation Vote. Results indicate a strong negative linear correlation between eye illuminance and the degree of eye?s openness in the direct sunlight scenario (p=-0.636; s=0.008) and in diffuse light scenario (p=-0.661; s=0.005), that could be the main predictor of visual discomfort. This experiment allowed us to explore eye behavior patterns that could be visual comfort indices under glare risk situations.O impacto a luz do dia no ambiente visual é fundamental para o trabalho no Ecrã de Visualização de Dados (EDV). Desempenho visual e conforto visual devem ser considerados em igual. O estudo (n = 16) foi realizado no laboratório experimental de iluminação. O trabalho de escritório com EDV foi avaliado utilizando a tarefa de Stroop em duas orientações: (com / sem presença solar no campo visual). A nossa hipótese afirma a existência de uma relação entre o comportamento ocular e conforto visual dos trabalhadores. Um “eye-tracker” foi desenvolvido para gravar os parâmetros gestuais oculares: pestanejar, direção do olhar, abertura dos olhos (Grau de abertura do olho) e tamanho da pupila, que foram correlacionados com a iluminância vertical no olho. Conforto visual foi avaliado com a escala de sensação de encadeamento. Os resultados indicam uma correlação linear negativa forte entre a luminosidade dos olhos e do grau de abertura de olho no cenário de luz solar direta (p = -0,636; s = 0,008) e no cenário de luz difusa (p = -0,661; s = 0,005), que poderia ser o principal preditor de desconforto visual. Esta experiência permitiu-nos explorar padrões de comportamento do olho que poderiam ser os índices de conforto visual em situação de risco de encadeamento.Fil: Yamin Garretón, Julieta Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; ArgentinaFil: Rodriguez, Roberto Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; ArgentinaFil: Pattini, Andrea Elvira. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentin

A Neurophysiologic Study Of Visual Fatigue In Stereoscopic Related Displays

Two tasks were investigated in this study. The first study investigated the effects of alignment display errors on visual fatigue. The experiment revealed the following conclusive results: First, EEG data suggested the possibility of cognitively-induced time compensation changes due to a corresponding effect in real-time brain activity by the eyes trying to compensate for the alignment. The magnification difference error showed more significant effects on all EEG band waves, which were indications of likely visual fatigue as shown by the prevalence of simulator sickness questionnaire (SSQ) increases across all task levels. Vertical shift errors were observed to be prevalent in theta and beta bands of EEG which probably induced alertness (in theta band) as a result of possible stress. Rotation errors were significant in the gamma band, implying the likelihood of cognitive decline because of theta band influence. Second, the hemodynamic responses revealed that significant differences exist between the left and right dorsolateral prefrontal due to alignment errors. There was also a significant difference between the main effect for power band hemisphere and the ATC task sessions. The analyses revealed that there were significant differences between the dorsal frontal lobes in task processing and interaction effects between the processing lobes and tasks processing. The second study investigated the effects of cognitive response variables on visual fatigue. Third, the physiologic indicator of pupil dilation was 0.95mm that occurred at a mean time of 38.1min, after which the pupil dilation begins to decrease. After the average saccade rest time of 33.71min, saccade speeds leaned toward a decrease as a possible result of fatigue on-set. Fourth, the neural network classifier showed visual response data from eye movement were identified as the best predictor of visual fatigue with a classification accuracy of 90.42%. Experimental data confirmed that 11.43% of the participants actually experienced visual fatigue symptoms after the prolonged task

Bifocal contact lenses: A review

A review of bifocal contact lenses has been formulated to introduce the reader to research in this area. Published literature and clinical use are incorporated into a tangible model that will allow a practitioner to understand the lens contructs, optics, and successful fitting methods. The article also contains a simplified fitting guide that can aid in the fitting of bifocal contact lenses. Some complications that commonly occur with these lenses, lens candidates, and special fitting applications are explored and fitting solutions identified. The guide can be utilized as an educational model to help incorporate bifocal contact lenses into a practice

Vestibular Symptoms, Balance and Vestibular Function in Patients with Vestibular Schwannoma

Bakgrunn: Vestibularisschwannom (VS) er en godartet svulst på den 8.hjernenerve som ofte fører til hørselstap, øresus, ustøhet og vertigo. Behandling avhenger av svulstens størrelse og om svulsten vokser, og inkluderer enten observasjon (wait-andscan), stråling eller operasjon. Man vet lite om det naturlige forløpet av sykdommen når det gjelder vestibulære symptomer og funksjon. Mål: Å undersøke hvordan vestibulære symptomer og funksjon påvirkes av et ubehandlet VS, både på kort og lang sikt. Materialer og metode: Pasienter med nylig diagnostisert, ubehandlet VS ble inkludert i periodene 2001-2010 og fra juni 2017 til juni 2019; henholdsvis en gruppe pasienter som ble fulgt opp regelmessig i inntil ti år og en tverrsnitts studie. Resultater: Ingen svimmelhet ble rapportert av 35% av pasientene. Moderat til alvorlig svimmelhet ble rapportert hos 31% og var assosiert med kanal parese og postural ustøhet. I gruppen uten vekst av tumor i oppfølgningsperioden (N=114) fant vi ikke signifikant økning av svimmelhet, postural ustøhet eller kanal parese. Vi fant videre at ustøhet ved posturografi predikerte vekst av tumor innen 3 år (OR=5,6 og 95% CI 2,6-11,8). 6-canal video hode impuls test (vHIT) og kalorisk prøve var de mest sensitive testene med sensitivitet på henholdsvis 51% og 47%. vHIT av posteriore kanal var ofte abnormal på den friske siden (17%). Kombinasjonen av kalorisk prøve og cervicale vestibulære myogene potensialer (cVEMP) økte sensitiviteten til 65% samtidig som bare noen få hadde abnormal test på non-tumor siden (6%). Konklusjoner: Majoriteten av ubehandlede pasienter med VS opplevde enten ingen svimmelhet eller kun milde symptomer. Funnene våre indikerer en god prognose når det gjelder vestibulære symptomer og vestibulær funksjon hos pasienter som behandles konservativt i form av wait-and-scan. Ustøhet målt på posturografi, predikerte vekst av svulsten innen 3 år hos pasienter med ubehandlet VS. En konsekvens av dette kan være at ustødige pasienter trenger mer aktiv oppfølgning. Kombinasjonen av kalorisk prøve og cVEMP var den mest nyttige, noe som skyldtes en relativ høy sensitivitet og en lav andel av abnormale resultat på den friske siden.Background: Vestibular schwannoma (VS) is a benign tumor on the 8th cranial nerve that often leads to hearing loss, tinnitus, unsteadiness and vertigo. Treatment is based on tumor size or whether there is growth of tumor, and includes either observation (wait-and-scan), radiosurgery or microsurgery. Little is known about the natural course of the disease when it comes to vestibular symptoms and function. Aim: To study how vestibular symptoms and function are affected by untreated VS, in a short- and long-term perspective. Material and methods: Patients with newly diagnosed untreated VS were included in the periods 2001-2010 and from June 2017 to June 2019. A cohort followed up regularly for up to ten years and a cross-sectional study, respectively. Results: No dizziness was reported by 35% of the patients. Moderate to severe dizziness was reported by 31% and was associated with canal paresis and postural instability. In the subgroup with no growth of tumor during follow-up (N=114) we found no significant increase in dizziness, postural unsteadiness or canal paresis. Furthermore, unsteadiness on posturography predicted tumor growth within 3 years (OR= 5.6, 95 % CI 2.6, 11.8). The 6-canal video head impulse test (vHIT) and the caloric test were the most sensitive tests with sensitivities of 51% and 47 %, respectively. Posterior canal vHIT often showed abnormal results on the non-tumor side (17%). The combination of caloric test and cervical vestibular evoked myogenic potentials (cVEMP) increased the sensitivity to 65%, while only a few had abnormal tests on the non-tumor side (6%). Conclusions: The majority of untreated VS patients experienced either no dizziness or only mild symptoms. Our findings suggest a favorable long-term prognosis for vestibular symptoms and functions in patients managed through a wait-and-scan approach without tumor-growth. The presence of unsteadiness, as measured by posturography, predicted tumor growth in untreated VS patients within three years. An implication of this could be that unsteady patients need more active management. The combination of caloric test and cVEMP was most useful, due to the relatively high sensitivity and low prevalence of abnormal tests on the non-tumor side.Doktorgradsavhandlin

Visual fatigue and the driver

The last fifty years of research on visual fatigue are surveyed, with special emphasis on results that may be important in the context of driving. Over that time, ideas about visual fatigue have varied, ranging from a broad application of the label eyestrain, to virtually any visual complaint (including poor acuity), to more specific applications of the term to mean visual discomfort associated with lengthy near-vision tasks. Much of the research reviewed concerns visual fatigue in the workplace, and places particular emphasis on extended use of video displays. One consequence of this emphasis on specific workplace circumstances is that substantial portions of the work on visual fatigue may not be fully applicable to driving. The mechanisms developed to explain workplace visual fatigue may not be strongly engaged in driving. This is especially likely for research that links visual fatigue to oculomotor changes in vergence and accommodation after near work. Visual fatigue in driving is likely to be more strongly related to mechanisms such as ocular surface irritation that may occur as a consequence of eyeblink suppression, or to declines in arousal level that may occur over the course of a lengthy drive. Research directions on possible links between visual fatigue and vehicle lighting are discussed, along with options for measurement.University of Michigan Industry Affiliation Program for Human Factors in Transportation Safetyhttp://deepblue.lib.umich.edu/bitstream/2027.42/61186/1/100999.pd

Event Detection in Eye-Tracking Data for Use in Applications with Dynamic Stimuli

This doctoral thesis has signal processing of eye-tracking data as its main theme. An eye-tracker is a tool used for estimation of the point where one is looking. Automatic algorithms for classification of different types of eye movements, so called events, form the basis for relating the eye-tracking data to cognitive processes during, e.g., reading a text or watching a movie. The problems with the algorithms available today are that there are few algorithms that can handle detection of events during dynamic stimuli and that there is no standardized procedure for how to evaluate the algorithms. This thesis comprises an introduction and four papers describing methods for detection of the most common types of eye movements in eye-tracking data and strategies for evaluation of such methods. The most common types of eye movements are fixations, saccades, and smooth pursuit movements. In addition to these eye movements, the event post-saccadic oscillations, (PSO), is considered. The eye-tracking data in this thesis are recorded using both high- and low-speed eye-trackers. The first paper presents a method for detection of saccades and PSO. The saccades are detected using the acceleration signal and three specialized criteria based on directional information. In order to detect PSO, the interval after each saccade is modeled and the parameters of the model are used to determine whether PSO are present or not. The algorithm was evaluated by comparing the detection results to manual annotations and to the detection results of the most recent PSO detection algorithm. The results show that the algorithm is in good agreement with annotations, and has better performance than the compared algorithm. In the second paper, a method for separation of fixations and smooth pursuit movements is proposed. In the intervals between the detected saccades/PSO, the algorithm uses different spatial scales of the position signal in order to separate between the two types of eye movements. The algorithm is evaluated by computing five different performance measures, showing both general and detailed aspects of the discrimination performance. The performance of the algorithm is compared to the performance of a velocity and dispersion based algorithm, (I-VDT), to the performance of an algorithm based on principle component analysis, (I-PCA), and to manual annotations by two experts. The results show that the proposed algorithm performs considerably better than the compared algorithms. In the third paper, a method based on eye-tracking signals from both eyes is proposed for improved separation of fixations and smooth pursuit movements. The method utilizes directional clustering of the eye-tracking signals in combination with binary filters taking both temporal and spatial aspects of the eye-tracking signal into account. The performance of the method is evaluated using a novel evaluation strategy based on automatically detected moving objects in the video stimuli. The results show that the use of binocular information for separation of fixations and smooth pursuit movements is advantageous in static stimuli, without impairing the algorithm's ability to detect smooth pursuit movements in video and moving dot stimuli. The three first papers in this thesis are based on eye-tracking signals recorded using a stationary eye-tracker, while the fourth paper uses eye-tracking signals recorded using a mobile eye-tracker. In mobile eye-tracking, the user is allowed to move the head and the body, which affects the recorded data. In the fourth paper, a method for compensation of head movements using an inertial measurement unit, (IMU), combined with an event detector for lower sampling rate data is proposed. The event detection is performed by combining information from the eye-tracking signals with information about objects extracted from the scene video of the mobile eye-tracker. The results show that by introducing head movement compensation and information about detected objects in the scene video in the event detector, improved classification can be achieved. In summary, this thesis proposes an entire methodological framework for robust event detection which performs better than previous methods when analyzing eye-tracking signals recorded during dynamic stimuli, and also provides a methodology for performance evaluation of event detection algorithms

Degree of eye opening: A new discomfort glare indicator

The degree of eye opening (DEO) is proposed as a new indicator of glare in sunny climates in the presence of direct sunlight. A laboratory experiment was carried out (. n=20) in a simulated office space where volunteers performed computer office tasks. Four lighting situations, based on ranges of vertical illuminance at the eye level were evaluated. By means of a visible spectrum eye-tracker DEO was registered in each scenario. The proposed indicator was obtained by mathematical iterations and showed a good correlation with: vertical illuminance at the eye (. r=-0.503; α=0.0001), Daylight Glare Probability (DGP) (. r=-0.649; α=0.0001) and Glare Sensation Vote (GSV) (. r=-0.580; α=0.0001). This new indicator operates in a broad range of lighting conditions, from a low vertical illuminance at the eye scenario with diffuse daylight to a very high vertical illuminance at the eye scenario with uncontrolled direct sunlight. The proposed new indicator satisfies the following criteria: high validity, reliability, diagnostic power and acceptability and it also addresses unresolved aspects of current glare predictive models: GSV, DGP and DGI.Fil: Yamin Garretón, Julieta Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Luminotecnia, Luz y Visión; ArgentinaFil: Rodriguez, Roberto Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; ArgentinaFil: Ruiz, María Angélica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; ArgentinaFil: Pattini, Andrea Elvira. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Luminotecnia, Luz y Visión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentin

Optometric management of video display terminal related vision problems

The growth of the digital market is progressively leaving a big impact on eye care professionals’ practice, whose rule is to permit a comfortable vision to their patients. Video display terminal related vision problems have drawn a particular attention, since the number of computer workers have increased over the last years. The popularity of smaller digital devices, such as smart phones and tablets, is increasing also among younger generations, as almost every child own one by the start of elementary school. Computers have also become an irreplaceable accessory, when talking about students in higher education institutes. The main objective of the thesis is to analyse Computer Vision Syndrome along with other vision related problems induced by other digital devices and a proper management of those. To alleviate the symptoms and to provide a comfortable vision, while using digital screens for several hours, optometrists have a wide selection of different treatment methods. Various researches, that approve better visual performance after the consultation with an eye care professional, have been studied. Prevention, including a proper positioning of the computer workstation or ergonomic mobile phone and tablet use, plays a significant rule. However, in the presence of the symptoms, depending on the nature of those, different approaches should be considered; the most common solutions to combat CVS are correction of refraction error, binocular and accommodative dysfunction, decreasing the amount of blue light entering the eye and dry eye management. Since the rapidly digitized world is changing people’s behaviour, the visual demands required for operating modern technology will continue to increase

Real-time blink detection as an indicator of computer vision syndrome in real-life settings: an exploratory study

With the increase in the number of people using digital devices, complaints about eye and vision problems have been increasing, making the problem of computer vision syndrome (CVS) more serious. Accompanying the increase in CVS in occupational settings, new and unobstructive solutions to assess the risk of this syndrome are of paramount importance. This study aims, through an exploratory approach, to determine if blinking data, collected using a computer webcam, can be used as a reliable indicator for predicting CVS on a real-time basis, considering real-life settings. A total of 13 students participated in the data collection. A software that collected and recorded users’ physiological data through the computer’s camera was installed on the participants’ computers. The CVS-Q was applied to determine the subjects with CVS and its severity. The results showed a decrease in the blinking rate to about 9 to 17 per minute, and for each additional blink the CVS score lowered by 1.26. These data suggest that the decrease in blinking rate was directly associated with CVS. These results are important for allowing the development of a CVS real-time detection algorithm and a related recommendation system that provides interventions to promote health, well-being, and improved performance.info:eu-repo/semantics/publishedVersio

TFOS lifestyle: Impact of the digital environment on the ocular surface

Eye strain when performing tasks reliant on a digital environment can cause discomfort, affecting productivity and quality of life. Digital eye strain (the preferred terminology) was defined as “the development or exacerbation of recurrent ocular symptoms and/or signs related specifically to digital device screen viewing”. Digital eye strain prevalence of up to 97% has been reported, due to no previously agreed definition/diagnostic criteria and limitations of current questionnaires which fail to differentiate such symptoms from those arising from non-digital tasks. Objective signs such as blink rate or critical flicker frequency changes are not ‘diagnostic’ of digital eye strain nor validated as sensitive. The mechanisms attributed to ocular surface disease exacerbation are mainly reduced blink rate and completeness, partial/uncorrected refractive error and/or underlying binocular vision anomalies, together with the cognitive demand of the task and differences in position, size, brightness and glare compared to an equivalent non-digital task. In general, interventions are not well established; patients experiencing digital eye strain should be provided with a full refractive correction for the appropriate working distances. Improving blinking, optimizing the work environment and encouraging regular breaks may help. Based on current, best evidence, blue-light blocking interventions do not appear to be an effective management strategy. More and larger clinical trials are needed to assess artificial tear effectiveness for relieving digital eye strain, particularly comparing different constituents; a systematic review within the report identified use of secretagogues and warm compress/humidity goggles/ambient humidifiers as promising strategies, along with nutritional supplementation (such as omega-3 fatty acid supplementation and berry extracts)