Liquid crystal clear

E-Vision of Virginia has developed electronic spectacles whose prescriptions
can be changed, doing away with the need to invest in new lenses (W0 01/02897).
The lenses are coated with a thin, transparent film of indium tin oxide and
filled with liquid crystals. Apply a small voltage to the film and the
refractive index of the liquid crystals changes, altering the prescription.
Power comes from a thin-film battery stuck to the arms of the frames, alongside
a tiny processor and a memory which stores the wearer’s prescription settings.
If you want to order specs online, you can e-mail your prescription…