Thoughts on interaction design for visually impaired users
Around 2 million people in the UK currently have some form of visual impairment (Tate et al, 2005), ranging from short-sightedness to partial blindness. That accounts for a large proportion of Internet users who are often unnecessarily let down by bad design.
This is why various guidelines and techniques have been put in place, such as the WAI AAA guidelines, detailing best practice for developing websites that everyone can use; not just those with 20/20 vision. The introduction of the Disability Discrimination Act in 1995 has made these guidelines an invaluable means to validate improvements in the accessibility of websites.
This is all good news and much progress has been made. The trouble is that these guidelines, although measurable and verifiable, only serve to make websites theoretically usable by visually impaired users. They do little to make the experience enjoyable or easy; just theoretically possible.
I recently conducted a series of usability tests with visually impaired users at the RNIB centre in Bristol and saw how much more work there is to do before the Internet is a truly universal place for everyone. As well as enabling us to design a beautiful, accessible, version of the website, the research also revealed some interesting guidelines that can be generalised across all interaction design.
White noise
All of the users we spoke to had software to help them navigate the web. In order for this software to work properly the code used to build the website must conform to certain standards and this is where the WAI AAA guidelines come into play. This software would zoom in on an area of the screen, enlarging text and images and worked really well on all the websites we looked at.
The trouble is that when you’re zoomed into a typical website you’ll find yourself looking at a lot of white background space. This creates glare which in turn strains eyes and limits the amount of time that can be spent using the website. Accessible versions of websites should therefore use dark backgrounds with light text. As part of our research we found dark navy blue backgrounds with light yellow text provided the most comfortable experience.
Images and layout
Many websites we looked at provided an accessible version that simply serialised the content, removing all images and designed layouts. This assumes that visually impaired users have no interest in images or layout and they only serve to complicate the experience. It turns out that images, maps and layout help visually impaired users make sense of the site, add useful context and increase the enjoyability of the experience. As one user said ‘I like looking at the images and maps, I can’t always make everything out very well but that doesn’t mean I don’t want it here’.
Decisions, decisions…
A couple of the websites we looked at had taken accessibility a step further by allowing users to select from a wide range of font sizes, types, colours and spacing along with background colours and layout options. After spending some time going through all these options most users were unsure when to stop tweaking it, less happy with the final result and frustrated from all the time spent choosing. Ultimately they all settled on a very similar set of options, involving a clear sans-serif font such as Verdana, light yellow on a dark blue background with the largest text size possible.
The time required to sort all this out combined with the possibility they may never return to the site made this an unsatisfactory experience. Users wanted fewer options and for those options to be targeted at their most common requirements.
Enjoyable accessibility
Improvements in accessibility are clearly being made and the Internet is a richer, more useful place as a result. The focus so far has been in coding accessible HTML and CSS and this does make it ‘possible’ for partially sighted users to explore the site. I think we can do better than that now and look to design websites that are more than just ‘possible’ to use. They should be enjoyable to use. For everyone.
About the author
James enjoys getting involved in projects and collaborating with clients to get the best results. He has carried out loads of user testing, using all sorts of materials to make them the best possible. He likes beer and playing golf (at the same time whenever that’s possible!). Email James, or call +44 (0)117 946 3930
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