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Engineers have developed a prototype tablet display that compensates for an individuals' vision problems.

The system uses software to alter the light from each individual pixel on the screen, based on the person's glasses prescription.

The researchers also added a thin plastic pin hole filter to enhance the sharpness of the image.

The team say the technology could help millions who need corrective lenses to use their digital devices.

Around one person in three in the UK suffers from short-sightedness or myopia. In the US, around 40% while in Asia it is more than half the population.

In recent years there have been a that have attempted to use computing screens to correct vision problems.

The authors of this say their prototype offers "significantly higher contrast and resolution compared to previous solutions".

The team from the University of California, Berkeley, working with colleagues at Massachusetts Institute of Technology (MIT), developed an algorithm that adjusts the intensity of each direction of light that emanates from a single pixel in an image, based on the user's specific visual impairment.

Their prototype used an iPod, with a printed pinhole mask attached to the screen. To check the images, the researchers used a digital single-lens reflex (DSLR) camera which was set up to simulate a person who was farsighted.

The altered images from the iPod appeared sharp and clear to the camera, showing that the prototype was effective in correcting this sight issue.

"The significance of this project is that, instead of relying on optics to correct your vision, we use computation," said lead author Fu-Chung Huang. "This is a very different class of correction, and it is non-intrusive."

The research team believe that their idea, when refined further, could be of benefit to people who suffer from more difficult-to-treat vision issues.

"We now live in a world where displays are ubiquitous, and being able to interact with displays is taken for granted," said Prof Brian Barsky, from UC Berkeley, the project leader.

"People with higher order aberrations often have irregularities in the shape of the cornea, and this irregular shape makes it very difficult to have a contact lens that will fit.

"In some cases, this can be a barrier to holding certain jobs because many workers need to look at a screen as part of their work. This research could transform their lives."

It should be stressed that while the research is at a very early stage, the engineers behind it the approach believe it has great potential, in the field of visual correction and beyond.

They envisage displays that users with different visual problems can view at the same time and see a sharp image.

"In the long run we believe that flexible display architectures will allow for multiple different modes, such as glass free 3D image display, vision corrected 2D image display and combinations of vision corrected and 3D image displays," the authors write.

No consideration has been given, at this stage, to the impact such a system might have on the battery life of digital devices. This could also be an important factor going forward.

The research will be presented at an international conference on computer graphics called SIGGRAPH, in Vancouver in August.