Search results for "Sensory system"

When virtual and real worlds coexist: Visualization and visual system affect spatial performance in augmented reality

2021

New visualization approaches are being actively developed aiming to mitigate the effect of vergence-accommodation conflict in stereoscopic augmented reality; however, high interindividual variability in spatial performance makes it difficult to predict user gain. To address this issue, we investigated the effects of consistent and inconsistent binocular and focus cues on perceptual matching in the stereoscopic environment of augmented reality using a head-mounted display that was driven in multifocal and single focal plane modes. Participants matched the distance of a real object with images projected at three viewing distances, concordant with the display focal planes when driven in the mu…

Electrofunctional features of the tilted disc syndrome.

1986

The ERG, EOG and VEPs of 15 patients with tilted disc syndrome were studied. The ERG showed abnormal amplitudes in about 1/4 of the eyes and the EOG values were pathological in 3 patients. It is probable that the abnormality of the inferior-nasal portion of the retina and retinal pigment epithelium seen in the tilted disc syndrome causes the changes in the ERG and EOG. Pattern VEPs latency was delayed in most patients. This finding is probably due to the poor focusing of the light in the retina.

Teprotumumab reduces extraocular muscle and orbital fat volume in thyroid eye disease

2020

PurposeThyroid eye disease (TED) is a progressive, debilitating and potentially vision-threatening autoimmune disease. Teprotumumab, a novel human monoclonal antibody, has been shown to reverse the clinical manifestations of TED. Patients receiving teprotumumab have been shown in two multicenter, randomized placebo-controlled trials to have decreased proptosis, diplopia and inflammation after 24 weeks of treatment. This study aims to analyse volumetric and inflammatory changes on orbital imaging prior to and after teprotumumab treatment from one of these trials.DesignRetrospective review.SubjectsSix patients enrolled in the phase III teprotumumab clinical trial (OPTIC, NCT03298867) with act…

Subjective photic phenomena with refractive multifocal and monofocal intraocular lenses. results of a multicenter questionnaire.

2001

Abstract Purpose To compare the incidence and severity of photic phenomena after the implantation of the Array® (Allergan) refractive multifocal intraocular lens (MIOL) and a monofocal IOL. Setting Multicenter study at Kiel, Mainz, Karlsruhe, and Bremerhaven, Germany. Methods The study comprised 231 randomly selected patients from 4 study centers. The patients had had uneventful phacoemulsification with implantation of a refractive MIOL (n = 138) or a monofocal IOL (n = 93). By questionnaire, patients were asked whether they experienced light sensations postoperatively (light streaks, halos, flare, flashes, or glare) that had not been noticed preoperatively. Additional questions evaluated w…

Temporal resolution and temporal transfer properties: gabaergic and cholinergic mechanisms.

2007

Temporal resolution is a basic property of the visual system and critically depends upon retinal temporal coding properties which are also of importance for directional coding. Whether the temporal coding properties for directional coding derive form inherent properties or critically depend upon the temporal coding mechanisms is unclear. Here, the influence of acetylcholine and GABA upon photopic temporal coding was investigated in goldfish, using flicker stimuli, in a behavioral and an electrophysiological (ERG) approach. The goldfish temporal resolution ability decreased from more than 90% correct choices at 20 Hz flicker frequency to about 65% at 45 Hz flicker frequency with a flicker fu…

Color stimuli perception in presence of light scattering.

2006

Perception of different color contrast stimuli was studied in the presence of light scattering: in a fog chamber in Clermont-Ferrand and in laboratory conditions where light scattering of similar levels was obtained, using different light scattering eye occluders. Blue (shortest wavelength) light is scattered in fog to the greatest extent, causing deterioration of vision quality especially for the monochromatic blue stimuli. However, for the color stimuli presented on a white background, visual acuity in fog for blue Landolt-C optotypes was higher than for red and green optotypes on the white background. The luminance of color Landolt-C optotypes presented on a LCD screen was chosen corresp…

Tierexperimentelle untersuchungen zur rolle von entzündungsmediatoren bei der hornhautneovaskularisation

1984

Experimental investigations concerning the role of inflammatory compounds in corneal neovascularization.Natural and synthetic inflammatory compounds were implanted in the corneas of rabbits to clarify the question whether corneal neovascularization is induced by stromal edema alone, or by neovascular mediators. It could be demonstrated that prostaglandin E1 and E2 have an angiogenetic capacity, whereas their precursor (arachidonic acid) as well as PGA1, A2, B2, I2 and Thromboxan A2 were inactive in this regard.Histology showed that corneal neovascularization is always accompanied by the invasion of polymorphonuclear leukocytes. Corneal edema in the beginning of vascularization can be explai…

2015

The combination of local orientation collinearity and spatial frequency contrast in contour integration was studied in two experiments using a 2AFC contour detection and discrimination task. Target contours were defined by local orientation collinearity, spatial frequency contrast between contour and background elements, or both cues. Experiments differed in the source of spatial frequency contrast by manipulating the spatial frequency of either contour or background elements. Cue summation gains, defined as the performance benefit of double cue conditions over single cue conditions, were evaluated and tested against the predictions derived from probability summation and linear summation. S…

Simple Configuration Effects on Eye Movements in Horizontal Scanning Tasks

2015

When reading text, observers alternate periods of stable gaze (fixations) and shifts of gaze (saccades). An important debate in the literature concerns the processes that drive the control of these eye movements. Past studies using strings of letters rather than meaningful text ('z-reading') suggest that eye movement control during reading is, to a large extent, controlled by low-level image properties. These studies, however, have failed to take into account perceptual grouping processes that could drive these low-level effects. We here study the role of various grouping factors in horizontal scanning eye movements, and compare these to reading meaningful text. The results show that sequen…

100 Years of Benham's Top in Colour Science

1995

For 100 years Benham's top has been a popular device demonstrating pattern-induced flicker colours (PIFCs). Results of early and recent investigations on PIFCs are reported and show that the phenomenon originates in phase-sensitive lateral interactions of modulated neural activity in the retina followed by additional spatial interactions in the visual cortex behind the locus of binocular fusion. Colour matches with normal colour stimuli indicate that S/(M + L) opponent neurons are involved. Dichromats do not find matching stimuli for all PIFCs. PIFCs may become useful in medical diagnosis. The phenomenon is interpreted as a side effect of a neural mechanism providing colour constancy under…