Not all people with epilepsy are badly affected by flashing lights and flickering screens. But help is available for those who do have photosensitive epilepsy, if they find that doing their work on campus computers triggers seizures.
A sensitivity to flashing patterns and lights is relatively rare: estimates suggest that around six thousand people are affected in the United Kingdom.
This type of epilepsy tends to affect young people: ten per cent of all new cases of epilepsy in those under 19 are photosensitive.
Many different types of seizures can be triggered by flickering screens, flashing lights, blinking cursors, geometric patterns and animations. For most people with epilepsy, the sensitivity is greatest at around 20 flashes per second or 20 hertz (Hz). However, flicker at 60Hz or more can trigger seizures.
The biggest single problem is fluorescent lighting in shared computer rooms. Well-maintained fluorescents flash at 100Hz and are unlikely to cause problems by themselves. A screen running at, say, 80Hz may appear equally flicker-free. But the lights and the screen can interact to produce the effect of a 20Hz flicker.
Some computer rooms are kept dark, but for students who are sensitive to screen flicker this is not necessarily an improvement. White- screen word processors produce very bright images on the screen. The large contrast between the screen image and the darkened room can sometimes increase the likelihood of seizures.
The risk is aggravated if students cannot take screen breaks without losing access to their terminals, as often happens when demand for computing facilities exceeds supply.
Filters may reduce reflected light but they cannot stop screen flicker. The only reliable solution is the purchase of a computer with a liquid crystal screen which can be taken to a safely lit study room. In most cases this will be a laptop computer with a good-sized high-quality screen.
Michael Harnor, a senior lecturer at Manchester Metropolitan University, advises students to look for special equipment to reduce the likelihood of seizures.
He says: "If using a computer is vital to your course, then in the UK a special equipment allowance is available along with the student grant and should be enough to cover the cost of a 'no-flicker' laptop computer."
Early indications are that the current local education authority practice of awarding disabled students an allowance if specialist equipment is required for study will be continued in some form. In 1998-99, the amount has been increased to Pounds 3,955 for the duration of the course.
Similarly, the research councils will consider making an award for specialist equipment for postgraduates with photosensitive epilepsy.
An independent assessment centre such as those licensed by the National Federation of Access Centres can help students with the application to the relevant LEA or research council. Students can also talk to their students union welfare centre, or their computing service disability representative who will know if any specialist centres for assistive technology exist at their university or college.
After a low-flicker computer has been purchased and properly installed, students should work in well-lit rooms. They should reduce the brightness of the screen, avoid white as the background of a word processor, take regular screen breaks and remove screen patterns and animations.
Reflections from windows and other people's high-flicker screens should be avoided.
Although increasing numbers of students are disclosing their disabilities to their institutions, many students do not discuss their epilepsy with others because they have experienced prejudice.
Others tend not think of themselves as "disabled". This usually means they have no idea that they may be entitled to additional support.
Further information: www.sussex.ac.uk/ Users/prpk1/flicker.html Jenny Gristock is a doctoral researcher in the science policy research unit, University of Sussex.