Bionic eyelid passes double take test

Most eye replacements do not look like the real thing

Doctors have developed a bionic eyelid which can blink like the real thing to help patients who have lost an eye and a lid due to illness.

When an eye and an eyelid are removed, often as a result of cancer, it can be very difficult for plastic surgeons to create a natural appearance.

Despite surgery, it is usually obvious that one side is artificial because of the lack of movement of that eyelid compared with the healthy side.

But, according to the medical journal The Lancet, a team from Humboldt University in Berlin has developed a false eyelid which closes simultaneously with the upper lid of the healthy eye.

The eyelid, which has been fitted to a patient who lost an eye as a result of having a tumour, is made from a latex membrane which is incorporated into a glass eye.

A tiny battery-driven motor opens the artificial eyelid in time with the real one.

The lid is tugged open by a thread spooled onto a roll behind the false eye.

It springs shut when the motor is stopped, due to the elasticity of the membrane.

The eyelids are synchronised by using a muscle signal from the real one to switch on the motor.

Passed blinking test

Researcher Dr Martin Klein, one of those who developed the eyelid, said that after 300,000 test blinks the device showed no sign of wearing out.

The electronics and battery were housed in an acrylic capsule mounted behind the glass eye.

The researchers wrote in the Lancet medical journal: "The cosmetic result was good. The artificial upper eyelid moved simultaneously with the healthy eye.

"The synchronisation was tested with video control in slow motion. With additional movement of the artificial eyelid the patient presented a much more natural appearance."