Yes / The purpose of this study was to isolate and quantify the effects of observer response criterion on perimetric sensitivity, response variability, and maximum response probability. Twelve people with glaucoma were tested at three locations in the visual field (age = 47-77 years, mean deviation = -0.61 to -14.54 dB, test location Humphrey field analyzer [HFA] sensitivities = 1 to 30 dB). Frequency of seeing (FoS) curves were measured using a method of constant stimuli with two response paradigms: a "yes-no" paradigm similar to static automated perimetry and a criterion-free two interval forced choice (2IFC) paradigm. Comparison measures of sensitivity, maximum response probability, and response variability were derived from the fitted FoS curves. Sensitivity differences between the tasks varied widely (range = -11.3 dB to 21.6 dB) and did not correlate with visual field sensitivity nor whether the visual field location was in an area of steep sensitivity gradient within the visual field. Due to the wide variation in differences between the methods, there was no significant difference in mean sensitivity between the 2IFC task relative to the yes-no task, but a trend for higher sensitivity (mean = 1.9 dB, SD = 6.0 dB, P = 0.11). Response variability and maximum response probability did not differ between the tasks (P > 0.99 and 0.95, respectively). Perimetric sensitivity estimates are demonstrably altered by observer response criterion but the effect varies widely and unpredictably, even within a single test. Response bias should be considered a factor in perimetric test variability and when comparing sensitivities to nonperimetric data. The effect of response criterion on perimetric response variability varies widely and unpredictably, even within a single test. / Supported by ARC LP130100055; ARC LP150100815 (AT and AMM), College of Optometrists Research Fellowship (JD).

Yes / Measuring the spatial extent of defects may be advantageous in advanced glaucoma where conventional perimetric sensitivity measurements are unreliable. We test whether suprathreshold tests on a higher density grid can more efficiently map advanced visual field loss. Data from 97 patients with mean deviation / Supported by a College of Optometrists Research Fellowship (to JD).

yes / There is limited information regarding the views of patients, as healthcare consumers, on visual field testing, and no information regarding their preferences for future test developments. This study aimed to increase knowledge of patients' subjective experience of visual field assessment and to explore their opinions and priorities regarding current active areas of research and development. Online questionnaire with purposive sampling design. Adults who regularly perform visual field tests in Australia who report having glaucoma or being at risk of glaucoma. An anonymous survey, implemented using the Qualtrics webtool, with both closed and open ended questions designed to explore opinions regarding visual field testing, visit attendance for perimetry, as well as priorities for developments. The survey assessed three domains: 1) opinions regarding visual field test duration and visit frequency; 2) subjective experience; and 3) perspectives on future developments for perimetry. 152 complete survey responses were obtained. The median (IQR) age of participants was 66 (60-72) years. Most participants (70%) had experience of performing more than 11 visual field tests. Participants recalled that they completed visual field tests in median of 6 minutes (IQR: 5-8 minutes) and were willing to accept additional time (median: 5, IQR: 3-6 minutes) to obtain more information. Participants were prepared to increase both the number of visual field tests per eye and the frequency of visual field tests (median: 3, IQR: 2-4 visits per year), in order to gain more information about their visual status. Regarding future developments, the most preferred option was "similar test times but an increase in the level of information about my visual field", which ranked significantly higher than all other options including "shorter test times that maintain the currently available level of information about my visual field." Our study confirms, in a different population and healthcare system, previous research reporting patient perspectives on visual field assessment. We further reveal that healthcare consumers show a strong preference for accurate information about their vision and report being prepared to undergo longer visual field tests or more visual field tests to achieve that outcome.

Este trabalho descreve o desenvolvimento de um instrumento automático para medida de campo visual do olho humano, baseado na ocorrência de potenciais visuais evocados O principal objetivo do estudo foi demonstrar que os potenciais visuais evocados (P100) observados na região occipital podem ser correlacionados à visão de flashes de fontes luminosas pontuais distribuídas sobre uma calota com a forma de um elipsóide deformado. Aplicou-se ao domo hemisférico uma distribuição de fontes luminosas pontuais que descrevem a forma do campo visual humano (limitado a 60º acima, 70º abaixo do eixo central, limitado a 60º no lado nasal e 105º no lado temporal de cada olho). A ausência de potenciais visuais evocados por flashes luminosos é utilizada como indicador de perda da sensitividade da retina. Detalhes do desenvolvimento deste instrumento e os resultados preliminares são apresentados. / An instrument for automatic in vivo evaluation of the human visual field boundaries based on the evoked visual potentials was developed. The main objective of this study is to demonstrate that evoked potentials (P100) over the occipital area can be correlated to the vision of punctual light flashes from a deformed ellipsoid-shaped calotte. A punctual light sources distribution that follows the human visual field (boundaries lying 60º upward, 70º downward from the central axis, limited to 60º in the nasal side and 105º on the temple side of each eye) was applied to the hemispherical dome. The absences of light flashes evoked potentials are used as an indicator of lack the sensivity of the retina. The details of the development of this instrument and preliminary results for in vivo eyes are presented.

Glaucoma is the second leading cause of blindness affecting over 60 million people worldwide. The objectives of this study were to expand the existing methods of trend analysis in visual field time series data testing to aid in the early and accurate detection of glaucoma progression. Visual field data including 54 locations for each of 140 eyes (one per participant among 96 cases and 44 controls) were evaluated using the Humphrey Field Analyzer II program 24-2 Swedish interactive thresholding algorithm (SITA) standard test strategy and Goldmann size III stimuli. One eye was randomly selected for the study and data were collected between 2003 and 2009. Two visual field examinations were conducted at baseline and at eight additional time points of visual field exams taken every six months for four years. Demographic, clinical, structural and other health data in the VIP study were collected from the electronic medical record and health questionnaires. A variety of pointwise linear regression (PLR) criteria have been proposed for determining glaucomatous visual field progression. However, alternative PLR criteria have only been assessed on a limited basis. The first aim of this glaucoma progression detection study thoroughly examined PLR cut-point criteria to maximize the sensitivity and specificity of this standard tool in visual field analysis. The pointwise linear regression A2 (PLRA2) method was used to analyze the data, and Ocular Hypertension Treatment Study (OHTS) data were used to validate the decision rule. Results showed that visual field trend analysis using PLR can be refined by adjusting the standard slope-based and significance level-based criteria. By considering more restrictive declines in visual field data (e.g., < -1.2dB/y, which is approximately 12 times the normal rate of age-related decay) and relaxing the significance level criterion of the PLR slope to p < 0.04 a high specificity can be maintained, while increasing the hit rate, i.e., the proportion of glaucoma cases in which progression was detected by PLR. This work serves to improve a familiar and commonly used method of time series visual field trend analysis that can be implemented quickly to improve early detection of glaucoma progression. The second aim of this project was to investigate the performance of the nonlinear exponential and tobit regression models relative to the normal regression model in the analysis of visual field decay. The goodness-of-fit, as measured by Akaike Information Criteria (AIC), and rates of progression obtained by fitting three alternative regression models to longitudinal visual field data were compared at the location level. The results showed that visual field trend analysis using the tobit regression model results in a better model fit to visual field data, increased precision in the estimation of the rate of progression, and provides a specific advantage in modeling data from cases with advanced glaucoma. The third, and final, aim of this glaucoma progression research project sought to determine if demographic, clinical and health factors, including intraocular pressure, retinal nerve fiber layer thickness, hypertension and diabetes, differ in participants whose visual field data are best fit overall by one statistical model compared to another. This was the first study to examine person-level factors that may affect the fit of proposed analysis models for visual field data, and to utilize bivariable and multivariable methods to understand patient-level predictors of visual field model fit. In the majority of eyes, the tobit model provided either a significantly better fit or there was no difference among models. Significant differences in patient characteristics included baseline MD and previous ocular surgery. This indicates that the tobit model may fit visual field time series data at least as well as the normal and nonlinear exponential models in all cases and controls; and in some advanced cases, it may provide a significantly improved fit. This research overcame critical barriers in visual field trend analysis by increasing the sensitivity of PLR methods and further developing methods using alternative distributions to determine significant loss of function within each visual field test location. Furthermore, results of this study will contribute to the ongoing improvement of visual field trend analysis and the early detection and treatment of glaucoma progression.

Grasping is fundamentally important for our successful interaction with the environment. Grasping with both hands is phylogenetically older than the hand yet its underlying mechanisms are poorly understood. The objective of this research is to examine bimanual grasping and its underlying mechanisms. Two experiments were conducted to examine whether bimanual grasping involves both hemispheres equally or only one dominant hemisphere, and to examine whether information crosses at an early visual level and/or at later sensorimotor/motor levels. The first experiment examined participants’ grasping and reaching movements while they fixated either to the left or right of the object. For the second experiment, EEG data was recorded while participants performed a similar task. The results from both experiments suggested that when we grasp an object with both hands, the left and right hemispheres control the action equally, and visual information is shared before it reaches areas that are involved in motor control.

Grasping is fundamentally important for our successful interaction with the environment. Grasping with both hands is phylogenetically older than the hand yet its underlying mechanisms are poorly understood. The objective of this research is to examine bimanual grasping and its underlying mechanisms. Two experiments were conducted to examine whether bimanual grasping involves both hemispheres equally or only one dominant hemisphere, and to examine whether information crosses at an early visual level and/or at later sensorimotor/motor levels. The first experiment examined participants’ grasping and reaching movements while they fixated either to the left or right of the object. For the second experiment, EEG data was recorded while participants performed a similar task. The results from both experiments suggested that when we grasp an object with both hands, the left and right hemispheres control the action equally, and visual information is shared before it reaches areas that are involved in motor control.

The research focuses on the role of top-down influences on selective attention across the attentional visual field. The attentional visual field is the subset of the visual field in which attentional processes take place. The size of the attentional visual field is relatively large compared to the areas considered by most empirical studies of visual attention to date. Three possible forms of top-down influence are examined: 1) the expectation of the size of the area in which the target is likely to occur; 2) the expectation of the direction in which the target is likely to occur; and 3) existing unconscious bias in the spatial distribution of attention. Results from Experiment 1 suggest that participants modify the size of the attended area according to their expectation of the location of the target. Experiment 2 demonstrates that focus of attention can be oriented toward the expected target direction. Experiment 3 reveals that, even when no conscious control is involved, the distribution of attention is biased toward certain areas. Theoretical considerations are discussed, including the introduction of a simple statistical model to assist in conceptualizing the modifications of the distribution of attention over the attentional visual field. Practical applications of the results are also discussed.

The research focuses on the role of top-down influences on selective attention across the attentional visual field. The attentional visual field is the subset of the visual field in which attentional processes take place. The size of the attentional visual field is relatively large compared to the areas considered by most empirical studies of visual attention to date. Three possible forms of top-down influence are examined: 1) the expectation of the size of the area in which the target is likely to occur; 2) the expectation of the direction in which the target is likely to occur; and 3) existing unconscious bias in the spatial distribution of attention. Results from Experiment 1 suggest that participants modify the size of the attended area according to their expectation of the location of the target. Experiment 2 demonstrates that focus of attention can be oriented toward the expected target direction. Experiment 3 reveals that, even when no conscious control is involved, the distribution of attention is biased toward certain areas. Theoretical considerations are discussed, including the introduction of a simple statistical model to assist in conceptualizing the modifications of the distribution of attention over the attentional visual field. Practical applications of the results are also discussed.

Bakalauro darbas skirtas žmogaus akipločio analizei ir jo tyrimui. Darbą sudaro trys skyriai. Pirmame skyriuje analizuojami pagrindiniai akiplotį nulemiantys veiksniai bei akipločio defektai. Antrame skyriuje – aptarti dažniausiai naudojami akipločio tyrimo metodai. Praktinėje dalyje analizuojami eksperimento metu gauti akipločio duomenys. Tyrimo metu pastebėta, kad skirtingų spalvų chromatinės akipločio ribos skiriasi. Eksperimento metu paaiškėjo, kad akiplotis siaurėja tokia seka: baltos, mėlynos, raudonos ir žalios spalvos. Akipločio ribos spalvotiems stimulams skiriasi priklausomai nuo to, ar stimulas stumiamas iš centro į išorę, ar atvirkščiai (pirmuoju atveju akiplotis didesnis. / The subject of the Bachelor’s work is to analyze and investigate the visual field. The work consists of three sections. The first section gives the analysis of the main determinants and defects of the visual field. In the second section, commonly used methods of the visual field investigation are studied. In the practical part of the work, the data of the visual field investigation are analyzed. It was noticed that chromatic visual thresholds of different colours differ. The experiment showed that the field of vision narrows in the following sequence: white, blue, red and green colors. Visual thresholds for color stimuli vary depending on whether the stimulus is moved from the center to outside or vice versa (the visual field is bigger in the first case.