Researchers at the University of California and EPFL in Switzerland have developed a contact lens which when used with a specially developed pair of spectacles, can give telescopic vision to wearers.
The prototype PMMA contact lens is 8mm in diameter, 1mm thick in the centre and 1.17mm thick in the magnifying ring. Its central region lets light though for normal vision and the magnifying ring sits in a ring around it.
The system, said to have been designed for patients with AMD, can magnify details by 2.8 times. Wearers can switch between normal and telescopic vision using specially adapted Samsung 3D glasses fitted with a polarising film in conjunction with the contact lenses.
‘Historically, Galilean telescopes have been tried with a combination of a negative contact lens eyepiece used in conjunction with a positive objective lens worn in a spectacle. The closer objective distance offers some improvement to the field of view which is always the major problem with a distance telescopic device,’ said Optician clinical editor Bill Harvey.
‘The new lens has a peripheral achromatic zone which appears to converge light which is then internally reflected within the lens to finally leave via a more centrally placed diverging surface. In this way the peripheral body of the lens acts as the tube by exploiting internal reflection.
‘The optics are interesting but the major foreseeable problem is one of wearability. In order to achieve the telescopic effect, the lens has a centre thickness of 1mm with a greater thickness at the point of objective telescopic activity which is likely to make the lens difficult to wear or tolerate,’ he added.
‘While image quality fell short of design goals, we have identified an all refractive achromatisation approach that offers improved performance and is the basis of ongoing research,’ concluded the scientists working on the project, which was supported by DARPA, a research arm of the US military.