john Gill technology header image

Methods for Improving Accessibility of Interactive Television Systems

J M Gill & S Perera


Universal design is imperative to ensure that everyone can access cutting edge technology.  Elderly people are thought to be unwilling to learn and interact with such devices and anxious of the effort required.  This is documented as being unfounded with most apprehension being based on a lack of familiarity or even contact rather than inability. 

A digital divide has arisen between those that have access to digital technology and those that do not [the majority of which are elderly people].  The internet is still for the privileged, TV should not be too.  Interactive digital television [iDTV] could enable on-line access without the need to purchase and learn the intricacies of computers.  An inclusive design premise aims to embrace everyone’s needs so if accessible, iDTV could bridge this gap.

For seamless functionality, usability based on a deep understanding of users needs should be a primary concern.  As people age they can suffer from a decrease in their sensory, mental and physical abilities.  Some visual impairments such as presbyopia, macular degeneration and cataracts are age related.  There is a high positive correlation between the prevalence of visual impairment and age, so designing for visually impaired people will benefit the increasing ageing population.  An untapped potential market is lying dormant.
Good design for people with impairments is frequently good design for everyone. 

There is little doubt that interactive digital television is a potential revolution in home entertainment enabling the convergence of many types of media.  Used as a communication device or information point nestled in the heart of the home, for many elderly and visually impaired people iDTV could improve their quality of life but only if it is accessible.

The iDTV industry is aiming for a stylish, engaging, entrancing, television environment with a high return on investment.  Many elderly and visually impaired people want the minimum amount of confusion within a practical system.  This appears to create a conflict of needs between industry and some viewers. Traditionally television is a social relaxing diversion so even the general public do not want to expend effort as they sit at a distance in a backwards relaxed position.  This disparity is not insurmountable.  By adopting a user-centred approach and finding out what people want from this media, industry’s mission can be complemented.

Unfortunately iDTV design has been based on the conceptual models of computers, keyboard-based systems and mobiles but television user’s, skills, goals and attitude of interaction differ.  It must be realised that iDTV is not a PC and therefore can not be treated as such which imposes various constraints.  Different display characteristics mean that websites for TV must be formatted so they can be viewed more effectively either through software or specialised sites.  Remote controls are less sensitive than computer pointing devices.  The widescreen format also places images in the lower acuity peripheral parts of the right and left visual fields. Viewers will not tolerate delays, online help or manuals.  ‘Downloads’ are an alien concept and will be rebuked if costly.

It is reasonable to take ideas for features from computer based models but not necessarily their implementation.  In many instances the iDTV system is rated as difficult to use but ‘analogue TV was easy to use’.  Freeman (2000) found that it was thought to be as hard as using a PC!  For people who are computer literate, the comparison with iDTV is useful.  But the TV audience is more diverse with some having no prior computer experience.  People whose experience is limited may not grasp affordances or contrasts between the systems.  Prior experience influences ability thereby affecting the interaction so experts and novices may require different features.  Furthermore certain content may be more suitable for certain users so customisation would be valuable.

Vague guidelines for iDTV determine the areas where obvious problems arise but where do the parameters lie?  What specifically do people want and require?  How should these features be designed?  If these are to be customisable options what is the best method of applying / altering options?  Further detailed work is necessary and being carried out by the RNIB Scientific Research Unit.  This will provide a basis from which the European CEN Standard 1332-4 for the coding of special needs on a smart card can be extended to be applicable to interactive television and next generation mobile telecommunication systems.


Dr John Gill (Chief Scientist) and Sylvie Perera (Human Factors Scientist) are with RNIB Scientific Research Unit, Falcon Park, Neasden Lane, London  NW10 1RN


John Gill Technology Limited Footer
John Gill Technology Limited Footer