Schools should consider buying new interactive whiteboards that cost twice as much as the standard models but eliminate the risk to pupil and teacher safety, according to a government-funded agency.
Becta, the body for ICT in education, says looking directly at the beam for too long can permanently damage eyesight.
"Ultra short throw" whiteboard projectors "provide a safer classroom environment" by preventing people from staring into the beam, according to Steve Creed, head of technical testing and evaluation at Becta.
"If you are a teacher using a (conventional) whiteboard normally, you shouldn't have a problem," he said. "But it is like staring at the sun, and if you have the kind of children who might force themselves to look into the beam for more than a couple of seconds as an experiment, they could do themselves some damage."
Conventional projectors can have a beam anything up to the length of a lecture theatre, while "short throw" models reduce the risk of people getting in the way, with a beam that is only 1.2 metres long.
Ultra short throw projectors are just 4cm from the whiteboard, meaning "there is no chance of anybody getting in front of the beam", Mr Creed said.
But he stressed: "Whiteboards have been in classrooms since 2004, and perhaps a bit before, and there is no evidence to suggest we need to panic about the dangers of standing in front of them.
"Regular and short throw projectors can be used safely if they are mounted securely to minimise any risk. But that is not to say they are all mounted in a safe way."
Mr Creed said schools should do their own risk assessments. Factors to consider included the likely behaviour of pupils using the room, and the height of the ceiling. High ceilings cut down risk because the beam can be projected above sight lines.
Becta has worked with the Health and Safety Executive to produce safety guidelines (see box).
A good quality ultra short throw projector can cost #163;2,000, compared with #163;1,000 for a conventional projector of equivalent quality.
Amanda Brown, head of employment conditions at teaching union the NUT, said: "The NUT has published extensive guidance on the safe use of whiteboard projectors and we welcome any improvements in technology which lead to a safer working environment for staff and pupils."
Throw some light on it: the safety tips
Avoid staring directly into projector beam at all times
- Minimise time standing facing into the beam
- Pupils should be adequately supervised when asked to point out something on the screen
- Users should try to keep their backs to the beam
- A stick or laser pointer should be used to avoid the need to enter the beam.