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Application of Mobile and Wearable Technology in Data Collection for Ophthalmology
Published in Ching-Yu Cheng, Tien Yin Wong, Ophthalmic Epidemiology, 2022
Ashwin Venkatesh, Pradeep Ramulu
Metamorphopsia is a perceived distortion of visual space, commonly seen in disorders of macular function. The ForeseeHome device (Notal Vision, Tel Aviv, Israel) uses preferential hyperacuity perimetry to measure visual distortions in age-related macular degeneration and is designed for unsupervised use by patients in their homes. The test involves 500 retinal data points over 14° of the patient’s central visual field, collected in approximately 3 minutes, and allows quantitative monitoring of changes in macular function in metamorphopsia with greater sensitivity than the Amsler grid.14 Results are automatically transmitted to Notal Vision’s Monitoring Center, where they are logged with all previous tests from that patient. Patients who generate an alert on the ForeseeHome test trigger an immediate recall to their ophthalmologist’s office for additional diagnostic testing and examination. The utility of this device is highlighted by the AREDS2-HOME clinical trial, which concluded that the ForeseeHome device enabled earlier detection of choroidal neovascularization in high-risk patients with age-related macular degeneration.15
Reflections of a “Pre-Nominal” Cross-Cultural Psychologist
Published in Walter J. Lonner, Dale L. Dinnel, Deborah K. Forgays, Susanna A. Hayes, Merging Past, Present, and Future in Cross-Cultural Psychology, 2020
One thing that becomes apparent is that cross-cultural psychology has become a healthier activity over the years, and this is not just because more and better antibiotics have become available. Let me explain: those of us who laboured as pioneers often worked in remote villages and were thus exposed, in my own case, to such afflictions as malaria or dysentery. We were in direct contact with people, and thus in a position to observe “novel aspects of behaviour”. Here is an example: I encountered a superbly skilled illiterate basket weaver, and commissioned him to copy a special kind of basket from a photograph. To my astonishment, the finished product turned out to be totally different from the picture, which he believed to have followed faithfully. This led on to a series of studies of 2D visual space perception.
Issues and Challenges in Designing P300 and SSVEP Paradigms
Published in Chang S. Nam, Anton Nijholt, Fabien Lotte, Brain–Computer Interfaces Handbook, 2018
Another paradigm for a P300 BCI is the region-based paradigm (RBP), where the choice of an object is split in dual selection levels (Fazel-Rezai and Abhari 2009). In this paradigm, visual space is divided into seven regions. The desired characters are split into seven groups, and each group is placed into a single region as shown in Figure 26.3. Depending on the level of interface, each group can contain either seven characters or a single character as in first level and second level, respectively. For any given spelling task, the user has a few seconds to focus on the characters before the action of each level. Instead of the rows and columns as in the Farwell and Donchin (1988) paradigm, regions are flashed in a random order by changing its color between black and white. Choice of color was justified for better contrast in each color transition. Both levels are needed to detect a single character. In short, first level is used to select a group of characters in a region, which contains the target character while the second level is used to select the single target character from the chosen region. Following the similar procedure of two levels for each character, all characters are detected one after another in a given spelling task. Each time a target is flashed, a strong P300 potential is expected in the EEG wave.
Impact of Alzheimer’s Disease in Ocular Motility and Visual Perception: A Narrative Review
Published in Seminars in Ophthalmology, 2022
As previously mentioned, an uncommon and incompletely understood visuospatial defect that can be present in AD is Balint’s syndrome.81,82 This syndrome is characterized by the presence of simultanagnosia (difficulty in locating, reaching, or attending to multiple items in a visual space), ocular motor apraxia (inability to maintain fixation on a specific point located in the peripheral visual field), and optic ataxia (inappropriate coordination of voluntary movements in response to a visual stimulus).82 Furthermore, other visual disturbances, such as difficulties in searching for objects (figure–ground discrimination), in finding the correct way in familiar surroundings (environmental agnosia),63 or in spatial recognition or spatial order memory (spatial agnosia),73 have also been described in patients with AD. Likewise, significant limitations in visual attention have been reported leading to problems in the development of daily life activities.59
Gaze Direction Changes the Vertical-Horizontal Illusory Effects on Manual Length Estimations
Published in Journal of Motor Behavior, 2021
Perceptuomotor control for manual length estimations, as determined through curved pointing movements, depended on configuration orientation. Directing movements rightward for rotated configurations resulted in manual length estimations greater than directing movements downward for upright configurations (Figure 5). Remember that participants produced a greater percentage of illusory perceptual responses for upright than rotated configurations (Table 1) to provide perceptual responses similar to elsewhere (Charras & Lupiáñez, 2010; Cormack & Cormack, 1974; Finger & Spelt, 1947; Künnapas, 1955; Mamassian & de Montalembert, 2010; Thompson & Schiffman, 1974; Wolfe et al., 2005). The greater overestimations of bisecting segment length observed for rotated compared to upright configurations in our study oppose, thus cannot be explained by, the corresponding perceptual judgments. The perceptuomotor differences by configuration orientation may result from perceptuomotor transformations of visual space, which differ for vertical and horizontal coordinates (Crawford, 1994; Soechting & Flanders 1989a, 1989b). Transformation inconsistencies would explain why the manual length estimations of the bisecting segment for rotated configurations often exceeded upright configurations, rather than the opposite as with perceptual responses.
Relating optical coherence tomography to visual fields in glaucoma: structure–function mapping, limitations and future applications
Published in Clinical and Experimental Optometry, 2019
Jonathan Denniss, Andrew Turpin, Allison M Mckendrick
In order to relate the degree of damage between OCT and visual fields on a localised scale, it is critical to ensure that corresponding locations from visual space and OCT landmarks are being compared. For outer retinal disease, such mapping between visual field space and anatomical features visible with OCT is relatively simple because readily observable damage to outer retinal layers causes a direct deficit in the detectability of light in that co‐localised region of retina and visual field. This direct mapping is not the case for glaucoma. Regional retinal nerve fibre layer (RNFL) damage that is quantifiable at the optic nerve head maps to large areas of the retina, including wide tracts of retina outside the region tested by standard assessment of the central visual field. Furthermore, in the macula, the retinal ganglion cells are displaced from their photoreceptors, leading to a spatial shift between retinal ganglion cell damage reported on OCT and the corresponding visual field locations.