Elemental Discoveries - August 2004, Issue 72

A site for sore eyes

News release from Australian National Science Week

Australian eye researchers are close to achieving what may be the perfect contact lens - one that can be left implanted in the eye indefinitely. Debbie Sweeney of the Vision Cooperative Research Centre says that clinical trials of the breakthrough technique will start within two years.

"The implantable contact lens, or corneal onlay, has been a research goal for many years," says Sweeney. "We've been able to develop our implantable lens because of the wide range of expertise which we could bring together in the Vision CRC. "We needed specialists in novel polymers, in the physics and chemistry of surfaces, in optical design and even in glues and adhesives," she says. "Then we needed cell biologists to understand the reaction of living to non-living tissue, and to monitor the movement of nutrients and oxygen within the eye itself. "And of course we will also depend on human volunteers to allow us to fine-tune the technique of implanting the lenses in living human eyes."

Sweeney says the technique involves gently removing the outer layer of skin on the cornea, and inserting a flexible polymer implant with a special adhesive backing. "In fact it is quite a simple surgical operation which can be finished in twenty minutes," she says. "This is far less invasive than corrective laser surgery, and it is also - if necessary - an easily reversible procedure. "A successful implant may have a life of between ten and twenty years," she says. "The epithelial cells of the eye's skin quickly grow over the surgical site, and the polymer lens itself is biostable - that is, it has no reaction to its living environment - and does not absorb anything from the surrounding material. It is also porous, allowing the necessary passage of the liquids and nutrients of the eye." She adds that this research answers a problem which has challenged eye and vision specialists for many years and will make contact lenses truly competitive with spectacles.

"Even in the nineteenth century, experimenters attempted to implant "Plexiglass" into the cornea, but this was inevitably rejected by the eye of the host," she says. "More recently, there has been some success with 'donated' corneas being sewn into the eye, but with these too there has been a continuing problem of rejection. "It has been the development of the right polymer, optically clear, porous and biostable, by our research team, which has made the long-term implant possible," she says. Researchers from CSIRO Molecular Sciences, Institute for Eye Research and Vision CRC form this team. Sweeney says that the implantable contact lens will be particularly important to patients with eye problems, who would otherwise be considering laser refractive surgery - an invasive and non-reversible procedure.

Coming in Issue 74:
Accidents will happen - human reactions to chemicals and biological reagents can end a career
Predicting climate change - As carbon dioxide levels double, what will really happen the day after tomorrow?

Also in Issue 73, September 2004:

Green silicon production - making the microelectronics industry favourite element
P2P for scientists - peer mentoring, helping students help each other
Women in science - smashing the glass ceiling
Academic poaching of researchers - plugging the brain drain
Permanent implantable contact lenses - does what it says on the tin
Profile of ETH Zurich - a profile of...
Paradoxical ozone - the paradox of ozone


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Read the Chymical Wedding List - bonus feature in Issue 71 of Elemental Discoveries; we've also got a new feature listing the elemental discoveries timeline.