Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Lens replacement material holds prospect of ’young’ eyes for people over 40

09.09.2003


A gel-like material being developed by scientists at the VA Hospital and Washington University in St. Louis could eventually mean the end of bifocals and contacts for millions of middle age and older people who suffer from presbyopia — literally "old vision." The material, which could be used to replace old hardened lenses in patients, including those with cataracts, was described today at the 226th national meeting of the American Chemical Society, the world’s largest scientific society.



While not a life-threatening condition, presbyopia affects nearly everyone over the age of about 40 or 45. As people age, according to one theory, the lenses in their eyes slowly harden making it more and more difficult to focus on nearby objects. The current solution for most people is reading glasses or contacts. Even people who undergo corrective laser surgery often still need glasses for reading and up close focusing.

"Our idea is that if we can remove the lens and put in a material that is soft, like a young healthy lens is at age 20, then they would have their accommodative ability restored," says researcher Madalene Fetsch. "They would be able to focus on near and far objects."


Fetsch, a graduate assistant in Washington University’s department of biomedical engineering, is working under the mentorship of Dr. Nathan Ravi, M.D., Ph.D., principal investigator in the development of the replacement lens material. He is an associate professor of ophthalmology and professor of chemical engineering at the school. He also is director of ophthalmology for VA Heartland hospitals in the Midwest.

The material, which is currently in lab testing, is a hydrophobically modified hydrogel. Hydrogels are used in many extended wear contact lenses.

"The gels can be made soft to the touch and have viscoelastic properties similar to that of the natural human lens," according to Fetsch. "At the same time, our material so far looks like it has the potential to be injectable, which means less invasive surgery."

Other research groups are also working on replacement lens materials, but Fetsch believes her material is different in several ways. One significant difference, she says, is reversible disulfide bonds. "This means that after forming the gel, we can reduce the bonds, liquefying the gel again so that it can be injected into the lens capsular bag." Once in the bag, the material reforms to a gel under natural physiological conditions.

One advantage of this is that only a very small injection hole is required to place the lens material in the bag, thus avoiding the common surgical technique of cutting a slit to insert a replacement lens. Fetsch says the hole would be small enough that stitches would not be required after the lens material is placed in the capsular bag.

Fetsch is hopeful that animal testing can begin in one year. But first, the researchers have to improve the materials’ refractive index — the degree at which it refracts light, which is key to how well you can focus with the material.

"Right now, in this particular system, that’s a little low," Fetsch admits. "It’s not good enough to be able to see more than blurry. But it’s something we think we can bring up with just simple modifications." Other scientists have been successful in improving the refractive index in similar soft gels, according to the researchers.

The material the research group is using to form the reversible bonds — acrylamide — is a known neurotoxin, but Fetsch doesn’t think that will be a problem because the acrylamide is polymerized.

"It sounds ludicrous to put [acrylamide] in the body, but the idea is that polyacrylamide when it’s in long chains is not toxic to the body as far as we know," Fetsch says. Additionally, before injection, thorough washing of the material would get rid of any traces of acrylamide, she adds.

The polymerization process also can be used for other biocompatible acrylamide derivatives, the researchers say.

While acknowledging that there is still a lot of work left before an injectable lens could become a reality, Fetsch has an idea of how the material might be introduced.

"Assuming that we made it all the way to human studies, we probably would first offer it to cataract patients because by that time they almost certainly have presbyopia and they’re looking at a similar surgery anyway." After that, Fetsch says, it could be offered to people with presbyopia who otherwise have healthy vision but don’t want to wear glasses or contacts.

The Veteran’s Administration Merit Review Grant provided funding support for the research.


The poster on this research, PMSE 317, will be presented at 8:00 p.m., Monday, Sept. 8, at the Javits Convention Center, North Pavilion, during Sci-Mix, and at 5:30 p.m., Tuesday, Sept. 9, at the Hilton New York, Rhinelander Center, during a joint PMSE/POLY poster session.

Madalene D. Fetsch is a graduate assistant in the Department of Biomedical Engineering at Washington University’s School of Engineering and Applied Science in St. Louis, Mo.

V. Nathan Ravi, M.D., Ph.D., is an associate professor of ophthalmology and visual sciences at Washington University’s School of Medicine and professor of chemical engineering at Washington University in St. Louis, Mo., and the director of ophthalmology for VA Heartland hospitals in the Midwest.

Michael Bernstein | EurekAlert!
Further information:
http://www.acs.org/

More articles from Health and Medicine:

nachricht New discoveries predict ability to forecast dementia from single molecule
12.12.2018 | UT Southwestern Medical Center

nachricht Pain: Perception and motor impulses arise in the brain independently of one another
12.12.2018 | Technische Universität München

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Magic number colloidal clusters

13.12.2018 | Life Sciences

UNLV study unlocks clues to how planets form

13.12.2018 | Physics and Astronomy

Live from the ocean research vessel Atlantis

13.12.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>