A new eye implant based on computer screens might mean the end of reading glasses. Postgrad research student Devesh Mistry, of the University of Leeds in England, is using liquid crystal to build an artificial lens which can focus itself based on the movement of the eye.
Once you hit 45 years old, it’s likely that the lenses in your eyes will harden, making them less able to focus. This condition, presbyopia, is usually corrected with reading glasses. “As we get older, the lens in our eye stiffens,” says Mistry. ”When the muscles in the eye contract they can no longer shape the lens to bring close objects into focus.”
Mistry’s research uses replacement lenses made of liquid crystals, usually seen in computer monitors, and TV and smartphone screens. These lenses would be inserted the same way as is done currently during cataract surgery, where non-adjustable lenses are used to replace natural ones: Surgeons use ultrasound to break up the lens, then suck it out, before inserting the new lens through a slit in the cornea.
LCDs are usually controlled using electricity. The pixels in a screen are switched from clear to opaque, allowing the backlight to shine through, and colored filters placed in front of the pixels tint them red, green, or blue.
The LCD lens is much simpler. Liquid crystals have another property: they change their refractive index (how much they bend any light passing through them) based on the pressure applied to them. This is how our natural lenses work, so our eyes can use existing muscles to bend the artificial lens, causing it to change focus.
The artificial lenses are still ten years out, but Mistry hopes to have functioning prototypes by the end of his studies. If successful, these lenses could make reading glasses obsolete, as well as improving life for cataract sufferers, who could get a double benefit from their lens replacement.