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Biomedical subjects

S Rushton

Publications and source records attributed to S Rushton.

4 recordsLinked to original sources

Natural problems for stereoscopic depth perception in virtual environments.

The use of virtual reality (VR) display systems has escalated over the last 5 yr and may have consequences for those working within vision research. This paper provides a brief review of the literature pertaining to the representation of depth in stereoscopic VR displays. Specific attention is paid to the response of the accommodation system with its cross-links to vergence eye movements, and to the spatial errors that arise when portraying three-dimensional space on a two-dimensional window. It is suggested that these factors prevent large depth intervals of three-dimensional visual space being rendered with integrity through dual two-dimensional arrays.

Accommodation, Ocular

Binocular vision in a virtual world: visual deficits following the wearing of a head-mounted display.

The short-term effects on binocular stability of wearing a conventional head-mounted display (HMD) to explore a virtual reality environment were examined. Twenty adult subjects (aged 19-29 years) wore a commercially available HMD for 10 min while cycling around a computer generated 3-D world. The twin screen presentations were set to suit the average interpupillary distance of our subject population, to mimic the conditions of public access virtual reality systems. Subjects were examined before and after exposure to the HMD and there were clear signs of induced binocular stress for a number of the subjects. The implications of introducing such HMDs into the workplace and entertainment environments are discussed.

Computer Simulation

The significance of peak expiratory flow rate in assessing prognosis of elderly patients undergoing operations on the hip.

Peak expiratory flow rate (PEFR) was measured using a Wright peak flow meter in 190 patients with fracture of the proximal part of the femur, and in 110 patients who underwent elective total hip replacement. PEFR was significantly lower in the fracture group than in the elective group when similar age ranges were compared. In the fracture group, PEFR of less than 100 was associated with a 69.6 per cent mortality rate, whereas no deaths occurred where the PEFR was greater than 300. It is suggested that the patients' PEFR is a good indicator of their prospects and it can be easily measured on admission.

Age Factors

The effect of prostaglandin synthesis inhibitors and diphosphonates on tumour-mediated osteolysis.

Previous studies have shown that the prostaglandin synthesis inhibitor indomethacin reduced osteolysis produced by the experimental VX2 carcinoma, probably by inhibiting the stimulation of osteoclasts by prostaglandin E2. This study was carried out to determine whether prostaglandin inhibitors affect the tumour osteolysis produced by human mammary carcinoma as well as the VX2 carcinoma. The effect of diphosphonates on reducing tumour osteolysis was also investigated, since diphosphonates directly affect bone resorption. The results indicated that various non-steroidal, anti-inflammatory agents which inhibit prostaglandin synthesis reduced the osteolysis produced by human mammary or rabbit VX2 carcinomas. The diphosphonate compounds also produced a significant inhibition of tumour osteolysis. The results confirm the findings of Powles and his colleagues (1) that aspirin (also a prostaglandin synthesis inhibitor) reduced the osteolysis induced by human mammary carcinoma. It is suggested that these agents be evaluated as adjuvant therapy in patients with apparently 'early' mammary cancer in a controlled clinical trial.

Animals