RESUMO
It has been demonstrated that optokinetic nystagmus (OKN) gain increases through attention to peripheral motion when the central visual field is occluded. However, how the properties of OKN change when two areas containing motion in different directions are presented in the peripheral visual field is still unclear. In this study, we investigated whether OKN corresponding to the attended motion in the periphery occurred while the observer was maintaining fixation at the center. We presented two areas with different directions of motion arranged on the left and right, top and bottom, or center and surrounding (concentric) areas in the display. Observers counted targets appearing on the attended area in the stimulus to maintain their attention on it. The results indicate that attention enhances the gain and frequency of OKN corresponding to the attended motion even in the case of stimuli having several areas with different directions of motion.
Assuntos
Nistagmo Optocinético/fisiologia , Humanos , Percepção de Movimento , Campos VisuaisRESUMO
Using physiological and psychological measurements, we carried out experiments to investigate the influence of viewing distance and TV screen size on visual fatigue and feeling of involvement using 17-inch, 42-inch and 65-inch displays. The experiment was an ordinary viewing test with the content similar to everyday TV programs for one hour including scenery, sport, drama, etc., with commercials sandwiched in between. The number of participants was 16 (8 persons aged 21-31, and 8 persons aged 50-70) for each display size. In all, 48 participants viewed 3 display sizes. In our physiological evaluation, CFF (critical flicker fusion frequency), blink rate and a sympathetic nerve activity index were used; and in the psychological evaluation, questionnaires and interviews were employed. Our results, based on physiological and psychological measurements, suggest the opti- mum viewing distance to be around 165-220 cm, irrespective of screen size. Our evaluations, which are based on optimum viewing distance for minimal visual fatigue and a closer feeling of involvement, might therefore not agree with the currently recommended viewing distance, which is defined as 2 or 3 times the display's height.
Assuntos
Astenopia , Televisão , Acomodação Ocular/fisiologia , Adulto , Astenopia/diagnóstico , Astenopia/etiologia , Astenopia/prevenção & controle , Meio Ambiente , Feminino , Humanos , Entrevista Psicológica , Masculino , Filmes Cinematográficos , Avaliação de Resultados em Cuidados de Saúde , Análise Espaço-Temporal , Televisão/classificação , Televisão/normasRESUMO
The authors report here the results of evaluation experiments designed to explore the effect of viewing distance on visual fatigue. Two kinds of visual content (normal content and content likely to cause visual fatigue) were used by means of physiological measurements of subject responses while viewing a 42-inch PDP display, followed by psychological evaluations in the form of post-experiment interviews. Both experiments showed that visual fatigue reached a minimum at a distance of 3 to 4 times the height of the display (3-4H; 165 cm-220 cm) and that sympathetic nerve activity peaked at around 3H. These results indicate that the ideal viewing distance for minimal visual fatigue and a closer feeling of involvement might be at around 3H.
