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Television systems and signals
Published in Geoff Lewis, Communications Technology Handbook, 2013
Dioptre (diopter) D. This is a term used to quantify the power of a lens or prism and measured in units of the reciprocal of length (m−1). Converging and diverging lenses are considered to have positive and negative values, respectively. For a lens, D is the reciprocal of the focal length and defined as follows: if the deviation of a ray passing through a prism is 1 cm measured at a distance of 1 metre, then the lens is said to have a power of 1 prism dioptre.
Laterality and performance: Are golfers learning to play backwards?
Published in Journal of Sports Sciences, 2022
Oliver R. Runswick, David L. Mann, Shivraj Mand, Alan Fletcher, Peter M. Allen
Carey and Hutchinson (2013) have shown that this effect was modulated by the hand used to carry out the task, suggesting some sort of sensorimotor relationship between hand and eye dominance. Therefore, ocular dominance was measured using a chart previously used in golf by Dalton et al. (2015) and was recorded using both hands. The chart was scaled for use at 3 m so the difference between adjacent lines is equal to 1 prism dioptre. Participants were therefore asked to point (with both hands interlinked) towards the cross in the centre of the chart whilst viewing binocularly from 3 m. This technique allows binocular vision to be maintained and should be used in tests for eye dominance (Laby & Kirschen, 2011). Each eye was then covered in turn and the participants indicated where their fingers were pointing on the chart when each eye was covered. Values to the left of the cross were considered negative and to the right of the cross positive. The individual scores from each eye were summed to provide a quantitative eye dominance score. Ocular dominance (OD) was then classified according to the following criteria: Strong right dominance OD > 4, Weak right dominance 2 ≤ OD ≤ 4, No dominance −2 < OD < 2, Weak left dominance −4 ≥ OD ≤ −2, Strong left dominance OD < −4. Positive scores indicated a right ocular dominance and negative scores a left ocular dominance.
Comparison of visual fatigue caused by head-mounted display for virtual reality and two-dimensional display using objective and subjective evaluation
Published in Ergonomics, 2019
Masakazu Hirota, Hiroyuki Kanda, Takao Endo, Tomomitsu Miyoshi, Suguru Miyagawa, Yoko Hirohara, Tatsuo Yamaguchi, Makoto Saika, Takeshi Morimoto, Takashi Fujikado
Twelve subjects aged 26.7 ± 4.1 years [mean ± standard deviation; range, 22–36 years] were enrolled in this study (Table 1). The mean refractive errors (spherical equivalent, SE) of the subjects’ right and left eyes were −1.90 ± 1.53 D (dioptre) and −1.81 ± 1.67 D, respectively. The best-corrected visual acuity at distant for all subjects was equal to or better than 0.0 logMAR (minimum angle of resolution). The mean near point of convergence was 2.16 ± 1.95 cm. The mean fusional vergence range was 29.0 ± 10.5 prism dioptre (PD), and all subjects had a stereoacuity of 1.60 log arcsec. The mean angles of deviation at near and distance were 8.1 ± 9.1 and 1.6 ± 3.6 PD, respectively.