Sufferers of cataracts and just about anyone over the age of 40 and suffering from presbyopia (aka farsightedness - inability to focus on close-up objects) may be helped by a new replacement gel material for eye lenses to restore the lens flexibility that is lost with age.
"The gel material is soft to the touch, and it has elastic properties similar to those found in the natural human lens," Fetsch says. "It also looks as if it has the potential to be injectable, which would mean it could be deliverd with less invasive surgery."
Ravi and Fetsch say that using molecular techniques, it's possible to change the artificial lens material from a gel to a liquid. That liquid then can become a gel again in the presence of oxygen in the body after it is injected into the capsular bag. The hope would be that only a very small injection hole would be required during cataract or other lens replacement surgery so that patients undergoing the operation would not require stitches.
The researchers expect to begin animal testing early next year. What they reported to the American Chemical Society was work that involved mechanical and physical testing of the hydrogel that was done in the laboratory. Before testing the hydrogel in animals, the researchers also hope to improve the material's refractive index — the degree at which it refracts light — a key to how well the eye can focus once the material is implanted.
"Currently, in this particular system, the refractive index has been a little low," Fetsch says. "It's not good enough to be able to provide much more than blurry vision."
But other researchers in Ravi's group, particularly research associates Hyder Ali Aliyar, Ph.D., and Paul Hamilton, Ph.D., have successfully formed several soft gels with the appropriate refractive index. "It's a very significant breakthrough," Ravi says.
The researchers admit there is still much work ahead before an injectable lens could be used in human patients, but Fetsch and Ravi expect it would be introduced into cataract patients first.
This latest report from a Washington University of St. Louis research led by Nathan Ravi MD PhD follows on the heels of an Australian group's report of the development of a competing material that holds promise for the same purpose. It seems very likely that within 10 years effective treatments for reversing age-related presbyopia will be available.
|Share |||Randall Parker, 2003 September 09 07:10 PM Biotech Organ Replacement|