The Oxford English Dictionary states that disability is:

“1. A physical or mental condition that limits a person’s movements, senses, or activities {and} 2. A disadvantage”.  [1.]

Whilst restricted mobility or complete blindness can often be identified by a persons behavioural patterns or assets – such as a guide dog, cane or wheelchair – so called invisible disabilities are very hard to recognise.

Those invisible – or also referred to as hidden disabilities [2.]  – can cause a variety of symptoms and problems some of which might only be temporary or occurring irregularly. A universal categorisation or classification is currently not in place and would be nearly impossible to establish. Some clinical pictures however include certain forms of auditory and visual impairments or chronic pain.

“Disability resides in the society not in the person.” [3.]

In contrast to the ‘Oxford English Dictionary’ definition, the previous statement found within the ‘United Nations enable’ set of definitions for disability makes one thing clear: The problems caused by a disability are not a direct result of physical, intellectual, sensory or mental impairment – it is merely the degree of societies disregard for this persons unique requirements to interact successfully with their environment.

The ‘World Health Organisation (WHO)’ supports the ‘United Nations’ definition and refers to disability as an “umbrella term for impairments, activity limitations and participation restrictions, referring to the negative aspects of the interaction between an individual (with a health condition) and that individual’s contextual factors (environmental and personal factors).” [4.] It further defines participation restriction as “a problem experienced by an individual in involvement in life situations.” [5.] These can include discrimination in the work place or limitations to transportation. Level of assistance, perception, categorisation and the degree of general acceptance for disability vary depending on the cultural setting and a person’s role in society.

These two opposing concepts are referred to as the medical model and the social model of disability. The social model of disability arose in America as a result of the human rights movement and is more suitable for this dissertations focus and analysis of exclusion caused by the design of airport navigation systems. [6.] In the UK alone there are roughly 1.7 million people either registered as blind, partially sighted or struggling with low vision.

“Many of these users are elderly. Four out of five people with serious sight problems are over 65. One in five people over 75 have a sight problem.” [9.]

One of the demographic groups at high risk of visual impairment is the older generations. “About 65% of all people who are visually impaired are aged 50 and older, while this age group comprises about 20% of the world’s population. With an increasing elderly population in many countries, more people will be at risk of age-related visual impairment.” [10.]  There are numerous types of visual impairments, some of which are inheritable, others occur more commonly with progressing age; some are either easily- or even self-corrected whilst others have more invasive consequences. Common symptoms include blurred and distorted vision and difficulties in colour differentiation. [11.]

  • normal vision
  • moderate visual impairment
  • severe visual impairment
  • blindness

Moderate visual impairment and severe visual impairment are grouped and often referred to under the term ‘Low Vision’.

For blindness the ‘WHO’ further states that it is a “severe sight loss, where a person is unable to see clearly how many fingers are being held up at a distance of 3m (9.8 feet) or less, even when they are wearing glasses or contact lenses. However, someone who is blind may still have some degree of vision.” [13.]

Oxford, 2005. Compact Oxford English Dictionary – Third Edition. Oxford: Oxford University Press; p.280 [1.]

The Open University, 2006. What are hidden disabilities? {online} {Accessed 29 October 2011} [2.]

United Nations, 2007. What Is Disability And Who Are Persons With Disabilities? {online} {Accessed 17 October 2011} [3.]

World Health Organisation and The World Bank, 2011. World report on disability {pdf} {Accessed 05 November 2011}; p.303 [4.]

World Health Organisation, n.d.. Disabilities. {online} {Accessed 17 October 2011} [5.]

More information compiled in Appendix 1[/ref]

Throughout the experience of navigating an airport, users are bombarded with visual and auditory information, their senses and cognitive abilities are being continually challenged. The loss or restriction of any of these capabilities could therefore have a great influence on the success of the experience.

By optimising the navigational strategy and communication systems to as many user groups as possible, airports will set a good foundation for universal access and usability of their service and product. Considering and implementing inclusive design practices and making them a standard in the design process will help shape society into a less disabling environment and is, as discussed in detail later, beneficial to everyone.

Since this dissertations’ focus lies on visual impairments it is further necessary to understand how these in particular are caused and  classified. A short introduction into the mechanics of human eyesight might prove helpful as well. More information compiled in Appendix 2[/ref]

 Visual Impairment

The ‘NHS’ web section about visual impairments gives the key facts that 314 million people worldwide are visually impaired, of which 14% are blind. 87% of all visually impaired people are expected to live in developing countries.

85% of cases of visual impairments and 75% of all cases of blindness could be prevented or treated successfully. NHS, 2009. Visual Impairment. {online} {Accessed 01 December 2011} [6.]

Royal National Institute of the Blind and International Society of Typographic Designers, 2005. Inclusive Design: Clear and Large Print Best Practice Guide for Designers. Tauntan: International Society of Typographic Designers; p.19 [9.]

World Health Organisation and The World Bank, 2011. World report on disability {pdf} {Accessed 05 November 2011} [10.]

For a more detailed list of visual impairments as well as their symptoms and causes, please see Appendix 3[/ref]

The ‘International Classification of Diseases‘ quoted on the ‘WHO Fact Sheet No.282’ differentiates between four levels of visual functioning: World Health Organisation, 2011. Visual impairment and blindness – Fact Sheet N°282. {online} {Accessed 01 December 2011} [11.]

NHS, 2009. Visual Impairment. {online} {Accessed 01 December 2011} [13.]