Article History
Received: 17 July 2019
Revised: 10 December 2019
Accepted: 19 December 2019
First Online: 7 January 2020
Compliance with ethical standards
:
: John Barbur is an inventor of AVOT tests (some employed in this study); an employee of City, University of London; and a director of City Occupational Ltd. (a City University spin out company setup to manufacture and supply AVOT tests). All the other authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study.