快猫短视频

A FALSE eye that swivels in synchrony with its natural partner is being
developed by engineers in Canada. They aim to make the false eye follow the real
eye鈥檚 motion so faithfully that it will look completely natural.

The implant is intended mainly for people who have had a malignant facial
tumour. This condition can cause catastrophic damage that requires large
portions of the face, sometimes including an entire eye socket, to be surgically
removed.

After the operation, patients wear specially made plastic mouldings, in which
a false eye may be set, held in place by surgically implanted magnets or
attached to spectacles. Though these make the face look complete, people can
immediately see that something is wrong because the false eye doesn鈥檛 move, says
Gary Faulkner, a mechanical engineer on the team at the University of Alberta in
Edmonton.

In the Canadian team鈥檚 system, an array of infrared detectors built into a
pair of spectacles tracks the movement of the real eye by looking for changes in
the wavelength of reflected light hundreds of times a second. This data is
translated into a signal that controls motors in the fake eye.

The team has managed to follow the lateral movement of the good eye with an
accuracy better than half a degree. This is what counts, says Faulkner, because
if the tracking is further out than this, people notice. The next goal is to
follow the eye鈥檚 vertical movement as well.

Eventually the team hopes to replace the motors with actuators made of shape
memory alloys, which use small temperature changes to induce motion. This should
make the eye almost silent. 鈥淗aving motors whirring around in your head is
something people would not like,鈥� Faulkner says.

By making the actuators very thin, Faulkner believes he鈥檒l be able to make
them cycle on and off rapidly without generating sufficient heat to damage
surrounding components and tissue. 鈥淎ny animation you can put into a prosthetic
will be a big help,鈥� says Geoff Wilcsek of Manchester Royal Eye Infirmary.