3D TVs can disorient the brain

London: Avoid 3D TVs as they can disorient the brain, causing eye strain, headaches, nausea and sickness, scientists warn.

And the closer one is to the screen, the worse one feels, making 3D TVs more problematic than cinema screens.

Studies show that in up to 20 percent of the viewers it could even induce physical sickness, the Daily Mail reported, quoting the New Scientist.

In one experiment, researchers at Eindhoven University in the Netherlands asked 39 people who could see 3D to read some text on a screen 10 feet away.

Seven of the group suffered symptoms that can lead to nausea, including double vision and eye strain.

The Royal College of Opthalmologists said that more research was needed on the long-term effects of 3D TV, but conceded that

short-term effects were visible.

Viewers will have a choice between two types of 3D TVs - active and passive - which show images in different ways.

An active TV will cost less, but will require special 'shutter' glasses. The basic idea is that the TV displays the programme in a series of rapidly alternating frames - left eye, right eye, left eye, right eye - changing at such a speed that the viewer cannot even detect it is happening.

The shutter glasses, which cost 50 pounds a pair and are powered by a small battery, block out one eye or the other on alternate frames at the same high speed, synchronising with the image being displayed on TV via a wireless connection to the set. The brain is thus fooled into creating a 3D image in the mind's eye.

The passive technology relies on a special polarising filter on the TV set to split the image into its left eye/right eye components.

The split picture is then viewed using a simple pair of polarising glasses - similar to the ones handed out in modern 3D cinemas - to create the 3D image.