Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hopkins study shows 30-day soft contact lenses pose very small risk of vision loss

02.12.2005


A team of researchers led by the Johns Hopkins Wilmer Eye Institute have determined that the corneal infection rate associated with the use of 30-day -extended-wear contact lenses made from silicone hydrogel is comparable to that previously reported for older lens types worn for fewer consecutive 24-hour periods.



The study, published in the Dec. 1 issue of Ophthalmology, recruited 6,245 patients, 64 percent of them women with an average age of 35, from 131 practices in North America between August 2002 and July 2003. All participants were prescribed and fitted with CIBA Vision NIGHT & DAY® silicone hydrogel soft contact lenses, to be worn for 30 consecutive 24-hour periods. Participants completed a baseline survey to collect information and potential risk factors for infections. At three and 12 months after enrollment, information regarding contact lens wearing schedules, discontinuation of lens wear and the occurrence of red and painful eye infection requiring medical attention was obtained.

Eighty percent of the participants in the study completed 12 months of lens wear and wore their lenses for three or more weeks continuously. The overall annual rate of evident corneal infection was 18 per 10,000. There were two cases of corneal infection with partial loss of vision and an additional eight cases without vision loss. The rate of infection was lower for users wearing the lenses for three or more weeks than for those wearing the contact lenses for less than three-week continuous periods.


"The incidence of vision loss as a result of corneal infections among users of the silicone hydrogel contact lens was low," said Oliver Schein, M.D., M.P.H. lead investigator of the study and the Burton E. Grossman Professor of Ophthalmology at the Johns Hopkins Wilmer Eye Institute. "The overall rate for corneal infection with the wearing schedule of the silicone hydrogel soft contact lenses for up to 30 nights was similar to that reported for conventional (HEMA) extended-wear soft lenses worn for fewer consecutive nights," he added.

Contact lenses are safe, but have some risks not associated with glasses, added Schein. "Daily wear rigid gas-permeable contact lenses appear to have the lowest risk for corneal infection, followed by daily wear soft contact lenses and seven- or 30-day-wear soft contact lenses," said Schein. "Not everyone can wear the lenses successfully for a full 30-nights, but the risk of infection does not appear to increase with greater number of consecutive nights of wear. This is a different pattern than we previously observed with conventional extended-wear soft lenses, where the risk did go up substantially with additional overnight use."

The study also points out that there are many choices for those who do not want to wear spectacles to correct their vision, including hard and soft daily-wear contact lenses, and refractive surgery, such as LASIK (laser-assisted in situ keratomileusis).

"Individuals tend to make choices based on factors such as comfort, convenience, personal preference and safety," notes Schein. "The data are solid that the risks are least with rigid and soft daily-wear contact lenses, more with overnight wear of contact lenses and most with refractive surgery," he adds.

The current study’s results should be viewed in light of the first studies to evaluate the original 30-day extended wear lenses, which were approved by the FDA in 1981. Prior to their approval, the original extended wear lenses had been shown in studies to be relatively safe, but as their popularity increased, many cases of corneal ulcers, caused by bacterial infection, resulted in severe vision loss for users.

Studies in the late 1980s showed that the risk of infection was four times greater for the first-generation extended-wear soft contact lenses compared to daily lenses. The risk of infection increased as the duration of consecutive use increased. As a result, the FDA reduced the allowed wearing time for extended-wear contact lenses to just seven consecutive days.

In 2001, the FDA approved CIBA Vision’s silicone hydrogel soft contact lenses for continuous wear up to 30 nights. These silicone hydogel lenses allow greater than four times more oxygen through the lenses than did the original extended-wear soft contact lenses and are therefore thought to be offer health benefits for the cornea However, because of the complications seen in the 1980s with the original extended-wear soft contact lenses and therefore the FDA mandated post-market surveillance studies for these new lenses, which the current study satisfies.

Other researchers who participated in the study include James M. Tielsch, Ph.D., professor in the Johns Hopkins Bloomberg School of Public Health; Joanne Katz, Sc.D., professor in the Johns Hopkins Bloomberg School of Public Health; Dennis O’Day, M.D., Eduardo Alfonso, M.D., John McNally, O.D., Robin L. Chalmers, O.D., Joseph Sholvin, O.D., and Mark Bullimore, M.C. Optom., Ph.D.

John Lazarou | EurekAlert!
Further information:
http://www.jhmi.edu

More articles from Studies and Analyses:

nachricht WAKE-UP provides new treatment option for stroke patients | International study led by UKE
17.05.2018 | Universitätsklinikum Hamburg-Eppendorf

nachricht First form of therapy for childhood dementia CLN2 developed
25.04.2018 | Universitätsklinikum Hamburg-Eppendorf

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>