Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Contact lenses are home to pathogenic amoebae

20.10.2008
Contact lenses increase the risk of infection with pathogenic protozoa that can cause blindness. New research, published in the November issue of the Journal of Medical Microbiology, shows that a high percentage of contact lens cases in Tenerife are contaminated with Acanthamoeba that cannot be killed by normal contact lens solution.

Acanthamoeba is one of the most common types of protozoa in soil and is often found in fresh water. Most species eat bacteria and some can cause infections in humans. One of the diseases caused by Acanthamoeba is called amoebic keratitis, which is an infection of the eye.

Around 85% of all amoebic keratitis cases occur in people who wear contact lenses. The infection is very painful and can cause blindness. As the amoeba can be found in chlorinated swimming pools and domestic tap water, people who wear lenses while swimming or use tap water to rinse their lenses have an increased risk of infection.

“The prevalence of this infection has risen in the past twenty years worldwide, mainly because more people are wearing contact lenses,” said Dr Basilio Valladares from the University Institute of Tropical Diseases and Public Health of the Canary Islands, University of La Laguna. “When people rinse their contact lens cases in tap water, they become contaminated with amoebae that feed on bacteria. They are then transferred onto the lenses and can live between the contact lens and the eye. This is particularly worrying because commercial contact lens solutions do not kill the amoebae.”

The scientists looked at 153 contact lens cases, 90 containing lenses, from people in Tenerife who were showing no symptoms of infection. 65.9 % of the cases and lenses were contaminated with pathogenic Acanthamoeba and 30% of the amoebae identified were highly pathogenic. No pathogenic strains were found in daily contact lenses but several pathogenic amoebae were isolated from monthly and bi-monthly lenses. The two year use lenses that were analysed contained a high percentage of pathogenic amoebae due to a lack of hygiene and poor care of the lenses.

“We tested the effect of two standard drugs on the amoebae. We found that the antibiotic ciprofloxacin and the antiseptic chlorhexidine both kill Acanthamoeba. However, the concentrations of chlorhexidine found in contact lens maintenance solutions are not high enough to kill pathogenic strains, so most lens solutions do not protect against amoebic keratitis,” said Dr Valladares.

“At the moment, we are developing a contact lens maintenance solution that can kill pathogenic Acanthamoeba species,” said Dr Valladares. “Studies have shown that these amoebae are more common among contact lens users in Tenerife than in Scotland, perhaps because of the warmer climate. Contact lens users are at greater risk of infection here and we hope we will be able to prevent and treat the diseases caused by these amoebae more effectively in the near future.”

Lucy Goodchild | alfa
Further information:
http://www.sgm.ac.uk

More articles from Health and Medicine:

nachricht NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures
17.11.2017 | National Institute of Standards and Technology (NIST)

nachricht High speed video recording precisely measures blood cell velocity
15.11.2017 | ITMO University

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: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>