A Six Million Dollar Man-style bionic eye, developed using space

Sunday Herald, The, Jan 6, 2002 by Stephen Naysmith

BIONIC eyes that can repair the vision of people with retinal damage will be given to human patients for the first time later this year, as technology developed in space turns fiction into reality.

In the 1970s, television's Six Million Dollar Man was given bionic eyes that could act as virtual binoculars, giving him superhuman sight. Researchers at the University of Houston have a more modest goal - restoring failing sight in elderly patients or those whose eyesight has been damaged.

Several forms of blindness and partial eyesight occur as a result of the failure of the rods and cones in the back of the human eye. These biological solar cells in the retina convert light into electrical impulses which carry information to the brain.

If they are damaged, or malfunction, blindness is inevitable. Hereditary disorders such as retinitis pigmentosa, which can strike at an early age, and macular degeneration, caused by ageing, are among the leading causes of sight loss.

Scientists at the Texan Space Vacuum Epitaxy Centre (SVEC) have now patented a solution, which involves implanting microscopic ceramic films into the eye to take over the function of damaged rods and cones.

The sensors are 'grown' atom by atom, using technology developed as part of a project to enable scientists to observe the production of minuscule atomic structures in outer space.

Each artificial retina will consist of 100,000 tiny ceramic detectors, each one-twentieth of the width of a human hair. As they react to light, researchers hope the receptors in the eye will learn to interpret the electrical impulses from the microdetectors instead of those from the malfunctioning rod and cone cells.

It is uncertain how well the brain will comprehend the unfamiliar signals. Scientists hope patients will adapt, though the learning process might be slow, like a child beginning to recognise shapes and colours.

Dr Alex Ignatiev, director of SVEC at the University of Houston, said: "There are some diseases where the sensors in the eye, the rods and cones, have deteriorated but all the wiring is still in place. If we could only replace those damaged rods and cones with artificial ones, then a person who is retinally blind might be able to regain some of their sight."

This is not the first time attempts have been made to build artificial retinas. However, earlier models have been silicon-based, which causes major problems. Silicon is toxic and reacts badly with fluids in the eye. Medical researchers also feared that silicon- based devices would block nutrients from reaching the eyeball.

"If you implant a large impervious structure in the eye, nutrients can't flow and it will atrophy," Ignatiev said. In contrast, the ceramic detectors are minuscule, five microns across - which is the size of natural cones - enabling nutrients to flow around them. The oxide-based ceramic film is also less likely to cause damage or become damaged itself.

"We are conducting preliminary tests on the ceramic detectors for biocompatibility, and they appear to be totally stable," Ignatiev explained. "In other words the detector does not deteriorate and neither does the eye."

The SVEC is part of a network of US research establishments designed to commercialise discoveries made in space. Ignatiev believes this is a perfect example of the space programme providing benefits to humanity, as well as commercial opportunities.

"We grew thin oxide films using atomic oxygen in low-Earth orbit as a natural oxidising agent. Those experiments helped us develop the oxide detectors we're using now for the bionic eye project," he said.

Doctors are now preparing for the first human trials of the implants. The sensors are so small that it is impractical for surgeons to handle them. Instead they are being attached to tiny pieces of polymer film, one millimetre square. After insertion into a "pocket" in the eyeball, the polymer film will dissolve in a matter of days, leaving behind a microarray of ceramic sensors.

Dr Charles Garcia of the University's medical school is to supervise the trials. Hundreds of patients have already contacted the university, eager to take part.

The process is relatively simple, Garcia explained, though its effectiveness is unproven: "An incision is made and the retina is elevated by injecting fluid underneath. Within that little blister, we place the artificial retina. It is a long way from the lab to the clinic. Will they work? We won't know until we implant the receptors in patients."

Meanwhile, another development has also given hope to those afflicted by blindness. Japanese researchers claimed yesterday that they had succeeded in growing the world's first artificial eyeball. So far, however, the Tokyo University scientists have only grown eyeballs from the cells of frog embryos, which they then successfully transplanted into a tadpole.