I wear spectacles to correct for myopia and astigmatism. Is it possible to create a program to adjust the image of a TV, mobile or PC monitor using my optical prescription such that I could view it without spectacles?
Dan O’Donovan Solihull, West Midlands, UK
The eye uses a lens to focus light on the retina at its back. It needs to do this because the iris is a circle rather than a tiny hole, so a circle of light enters the eye.
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All of the light from each point on, say, a computer screen reaches the lens and is then redirected to one point on the retina. This relies on the lens changing shape so that it can refract the light by the correct angle.
As no program can adjust the path of the light as lenses do, the screen can’t seem to be a different distance to the lens than it actually is, so the simple answer to this question is no. However, placing a magnifying lens, such as a fresnel lens, over the screen may help with myopia.
Graham Jones Bridgham, Norfolk, UK
Institute of Technology and the University of California, Berkeley, developed a prototype display that can be viewed by people who are near or far-sighted without the need for glasses. It involves placing a second screen covered in pinholes in front of the image, as well as software to adjust the screen picture so that slightly different images reach each eye. This acts in a similar way to a lens, redirecting the path of the light such that each of a person’s lenses can focus it. However, the technology doesn’t seem to be available yet.
Eric Kvaalen Les Essarts-le-Roi, France
Astigmatism results from irregularities in the shape of the cornea or lens. It might be possible to adjust the image for the astigmatism of one eye, but then it wouldn’t be right for the other.
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