More Americans are becoming nearsighted, but it is not clear why, U.S. researchers reported on Monday.

They found more than 40 percent of Americans aged 12 to 54 developed myopia between 1999 and 2004, compared to just 25 percent in 1971 and 1972.

Their findings, published in the Archives of Ophthalmology, could be important for health policy, given the billions of dollars spent each year in caring for people with myopia.

The likely cause is less outdoor time and more activities requiring close-up viewing such as text-messaging, playing hand-held video games and Web surfing, said the study’s lead author, Susan Vitale.

 

When you take eye drops, blinking and your natural tears can mean that as little as 1 percent of the drug actually goes into your eye.

However, when it comes to medication, such reactions are less than favourable and cause as little as 1 to 7 percent of the dose is actually absorbed by the eye.

To combat this problem, a research team, led by Daniel Kohane, MD, PhD, director of the Laboratory for Biomaterials and Drug Delivery at Children's Hospital Boston, has created special contact lenses that can gradually dispense a constant amount of medication to the eye, at adjustable rates.

Kohane and colleagues at the Department of Chemical Engineering at the Massachusetts Institute of Technology (MIT) created a two-layer contact lens with an inner drug-bearing biodegradable polymer film known as PLGA.


In laboratory testing, the prototype lenses dispensed ciprofloxacin (an antibiotic often used in eyedrops) for 30 days, the longest duration for which contact lenses are currently approved by the FDA; in some tests, the lenses continued releasing drug for up to 100 days. The amounts dispensed were sufficient to kill pathogens in a laboratory assay.

The researchers have started testing the lens in animals and plan to begin human testing as soon as possible.


(The lens has been described in the July issue of Investigative Ophthalmology and Visual Science. (ANI)|}

> Learn how to get disposable contact lens

Contact lenses ought to be a convenient alternative to awkward or uncomfortable eye glasses, but the inappropriate storage and misuse of contact lens solutions can lead to painful eye infections and even blindness, the Food and Drug Administration reminded consumers.

The FDA said people who do not follow instructions for contact lens care and use might increase their risk of serious eye infections that can lead to blindness.

The FDA is again stressing the importance of proper handling and cleaning of contact lenses and advising consumers to always completely empty the solution out of contact lenses after each use.

To support proper cleaning and storage, the FDA has developed a new video on contact lens safety, which can be found on the FDA's Web site (www.fda.gov), along with an in-depth Consumer Update article.

Other important lens care tips from the FDA include:

-- Do not top off or reuse lens cleaning solution.

-- Use a contact lens solution to clean, rinse, and then air dry contact lens cases after each use.

-- Do not expose contact lenses or lens storage cases to any type of water or other non-sterile solutions.


The FDA has now released a public advisory designed to educate contact-lens wearers about the proper care and use of saline solutions in an effort to avoid severe complications.





Earlier this year, the FDA held a workshop along with eye care professionals to develop a set of guidelines for evaluating contact lens solutions. The FDA is still working on compiling rules for manufacturers and possibly changing labeling for the products to warn users of the potential for injury.

For more consumer information and tips on contact lens, visit Contac Lens Consumer Guide.