Eyestrain risk played down

Viewing a 3D film at the cinema is unlikely to cause significant asthenopia, an investigation has concluded.

The review by Dr Peter Howarth of Loughborough University, published in February's Ophthalmic and Physiological Optics (31: 111-122), comes in the wake of a spate of reports in UK and global media warning of the potential risks of viewing 3D films (News 20.1.11).

The review noted the lack of research supporting any possible adverse consequence relating to the 3D image. The representation of a 'real-world' image from a flat screen did require some flexibility of the accommodation-convergence ratio of people with normal binocular vision. However, as the images presented usually corresponded to those at infinity then this tolerance requirement was small and unlikely to cause problems. There was likely to be some process of adaptation on the part of the viewer which made asthenopia less likely once the viewer adapted to the image.