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Injectable gel may replace aging or ailing lens in eye Treatment could cure cataracts, presbyopia

By Ying Lou , USA TODAY
October 30, 2003

Gel-like material may one day replace diseased or aging lenses in the human eyes for people who have cataracts or presbyopia, a problem that requires bifocals.

Researchers are developing this new material, which could be injected into the human eye and function like a healthy lens. The normal functioning human lenses, through their flattening or thickening, help people see both distant and close objects. The new material would be flexed by the ciliary muscles of the eye to provide adjustments needed to see objects near and far.

The idea of finding a flexible material capable of replacing the human lens has been examined for years. But according to Nathan Ravi, associate professor of ophthalmology and visual sciences at Washington University in St. Louis , the major contribution of his group is identifying the material composition that mimics the lens properties.

The old lens material would be surgically removed from the lens' capsular bag, the part in the eye that holds the lens, and the hydrogel would be injected to mimic the young human lenses.

''People's near or close-up vision worsens at the peak of their career, and thus it causes great loss in productivity,'' says Ravi , who also is an affiliate professor of chemical engineering.

The National Institutes of Health estimates such loss at about $10 billion a year in the USA , he says.

The traditional way to cure cataracts would be to remove the lens material in the eye and substitute it with a plastic lens.

Although the technology to perform cataract surgery is already mature and the surgery can be performed within a few minutes, the plastic substitute cannot change focus automatically, and so patients would still have to wear glasses, Ravi says.

Robert Maloney, a spokesman for the American Academy of Ophthalmology and director of Maloney Vision in Los Angeles , says the idea of injectable lenses has been kicking around for 20 years.

''There are two major problems with this technology. One is, how do we determine how much to inject into the eyes? And the other is, when we make a hole to inject the material, how do we prevent it from leaking out the hole?'' Maloney says.

After eight years of research, Ravi and his researchers believe they have found ways to tackle the problems. Don't expect that this gel will be available immediately, however.

Animal tests will begin in March. Ravi says he expects the technology to be used as a treatment for humans in three to five years.