Colour in employment
Ben Evans writes about the recent Colour Group Symposium at City, University of London
Over 60 people, from a wide variety of backgrounds and travelling from as far away as Australia, gathered at City, University of London on the 23rd and 24th April 2018 for a two day symposium about colour vision and employment. The symposium aimed to increase awareness of the problems involved in both setting and enforcing minimum colour vision requirements within occupations, and to discuss new approaches to colour vision assessment that can reduce variability and minimise unfair discrimination.
Colour vision standards
With approximately 8% of males and 0.5% of females having some form of congenital colour vision deficiency as well as the increased use of colour in occupational environments (due largely to rapid advances in colour display technologies and lighting systems) it has become more important to be able to screen efficiently for colour vision deficiency and to accurately quantify the severity of colour vision loss.
With the navigational challenge of seeing colour-coded lights in our rock-strewn coast, it is not surprising that seafarers were one of the first occupations to introduce occupational colour vision standards. For over 50 years lantern testing was the norm. We were fortunate enough to witness a demonstration of one of the very first lantern tests in the first talk of the day, by Tim Carter, along with an overview of the history of occupational colour vision testing with a focus on the requirements for seafarers. Following this John Barbur from City questioned the traditional justification for setting minimum colour vision requirements in visually-demanding occupations. He then proposed a new justification which ensures that all applicants that can carry out the most demanding, safety-critical, colour-related tasks with the same accuracy as normal trichromats pass and are not therefore discriminated against on the basis of their colour deficiency.
Stuart Mitchell reviewed the evolution of regulations for colour vision in aviation, the methods employed in testing as well as the challenges in applying and implementing tests from the perspective of the civil aviation authority (CAA).
Following a refreshing tea break, packed with discussions in small groups and around posters, the meeting reconvened with a detailed presentation by John Parkes who discussed the current Australian occupational colour vision standards as well as the risk assessment framework used to review them. Two presentations followed by Anya Hurlbert and Ché Donald which described many issues with the colour vision standards and assessment protocols in current use by the UK police force. Both presentations highlighted the large statistical variability in the outcome of current tests and protocols and the difficulties of relating the severity of colour vision loss to the actual task requirements the police officers encounter routinely.
More discussions took place over lunch which was followed by two presentations by Gabriele Jordan and John Barbur on the underlying mechanisms and outcomes of anomaloscope match parameters, an internationally recognised colour vision test . The advantages of anomaloscope matches in identifying the class of colour deficiency and the difficulties of using the match parameters to quantify the severity of colour vision loss in relation to employment were discussed and emphasised in both talks. Peter Thomas then described the occupational colour vision requirements (or lack thereof!) in the medical profession and the ‘don’t ask, don’t tell’ culture that has developed as a result.
Refreshed by another tea break (when in England...) City researcher Marisa Rodriguez-Carmona and Adrian Chorley discussed the most well-known form of colour vision assessment, the Ishihara test. Marisa described the ‘balancing act’ that commonly occurs when a certain number of errors on the Ishihara test are allowed in an attempt to improve the specificity of the Ishihara plates. Adrian carried these concepts forward and, in his presentation, he outlined two modifications that can be made to the Ishihara test to try to increase the specificity as well as outlining some of the methods that are employed by individuals who try to memorize the Ishihara plates.
Classifying colour vision
Vilhelm Koefoed, continued where Tim Carter had left off earlier in the day, by providing a reflection on the need for colour vision classifications and their occupational suitability for maritime environments. The first day closed with a presentation by Peter Davidson, outlining the efficacy of a range of colour vision tests in the diagnosis of protanomaly and protanopia – two types of red-green colour deficiency - as well as highlighting the impact these colour deficiencies can have upon everyday life.
Lively discussions and networking continued in the symposium dinner late into the evening.
The second day of the symposium began bright and early with a short presentation by John Barbur on the history of colour vision research at City and the contributions made by many of its academics to occupational colour vision assessment over decades. Dozens of researchers were mentioned and particular tribute was paid to Robert Fletcher and Janet Voke for their contribution to the Colour Group and occupational colour vision research. Other important aspects of colour deficiency were highlighted in Kathryn Albany-Ward who discussed the importance of screening for colour vision deficiency in schools as well as the key role optometrists have in achieving this.
Begum Ulusoy gave a unique talk about the ideal colour for a work space, touching upon the apparent chromophobia of designers and the habituation that has led to white being seen as the optimal colour without any real evidence to suggest this is the case. We were pulled back into the world of colour vision testing by City researcher Ben Evans who discussed the suitability of the Farnsworth D-15 test for modern vocation guidance, the large statistical variability in D15 outcomes as well as the lack of agreement with other methods of colour vision assessment.
After a brief intermission, presentations by Cord Huchzermeyer and Roopa Vemala discussed acquired colour vision deficiency. Cord provided an extensive overview covering many different types of acquired colour vision deficiency that ophthalmologists may encounter and how they can be detected. Roopa presented results in patients with age-related macular degeneration which revealed the massive loss of both red / green and yellow / blue chromatic sensitivity in virtually every patient with AMD.
In the final talk of the symposium Galina Paramei described the way colour vision decreases with age. Although these effects are inevitable, acquired loss of colour vision is more pronounced above 60 years of age.
Following a break for lunch the final session of the symposium was an extended practical session, allowing attendees to get ‘hands on’ with a number of the colour vision tests in current use in occupations.
The symposium successfully highlighted many of the problems experienced by occupational practitioners and the difficulties involved in setting and justifying minimum colour vision requirements within occupations. The variety of participants including vision scientists, optometrists, ophthalmologists, occupational physics, regulatory bodies, a Navy Surgeon-General, a union official, an occupational therapist, a mother activist for colour deficient children, made this symposium truly unparalleled in its ability to connect people, as acknowledged in the very positive feedback received from participants. Overall, the symposium was considered to have been extremely informative, timely and a valuable forum for the exchange of ideas.
This meeting was made possible with the generous support of City, University of London and the Colour Group of Great Britain. The meeting was also supported by City Occupational Ltd. and Cambridge Research Systems. Finally, the meeting would not have been possible without the hard work of the symposium organizers, Marisa Rodriguez-Carmona and John Barbur.
The anomaloscope is an internationally recognised colour vision test (invented and used since 1907). It works by using the principle of colour matching to test for red-green colour vision deficiency.