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 Investigators may unlock mystery of how staph cells dodge the body's immune system
22.09.2017 | Cedars-Sinai Medical Center

nachricht Monitoring the heart's mitochondria to predict cardiac arrest?
21.09.2017 | Boston Children's Hospital

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: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>