UV-blocking silicone hydrogel contact lenses can reduce or eliminate harmful effects from the sun’s UV rays, according to a study published this month in Investigative Ophthalmology & Visual Science, an official journal of The Association for Research in Vision and Ophthalmology (ARVO).

Overexposure to UV light can cause harmful changes in the cornea, conjunctiva and lens, including cataracts, according to the investigators and authors of the article, “Prevention of UV-Induced Damage to the Anterior Segment Using Class I UV-Absorbing Hydrogel Contact Lenses.”

In the study, 12 rabbits were assigned to one of three treatment groups:

1. Those wearing a UV-blocking silicone hydrogel contact lens.
2. Those wearing a silicone hydrogel lens that doesn’t block UV.
3. Those wearing no contact lenses.

For five days, the animals were exposed to UV radiation capable of producing corneal changes. Only the rabbits who wore the UV-absorbing contacts were not affected by the exposure.

The UV-absorbing contact lenses used in the study were made of a silicone hydrogel material called senofilcon A. The material is used to produce Acuvue Oasys disposable contacts.

Heather Chandler, PhD, from Ohio State University’s College of Optometry, was lead investigator in the study. “The data generated from this study could support the use of UV-absorbing contact lenses and greatly impact the health of a large number of people,” Dr. Chandler said in an ARVO press release this week.

The study was supported by Vistakon, a division of Johnson & Johnson Vision Care, Inc.

Researchers are developing contact lenses that darken automatically in sunlight, similar to photochromic lenses available for prescription glasses. The contacts are treated with sun-sensitive dyes that darken when exposed to ultraviolet light, which is harmful to eyes.

Earlier attempts to make photochromic contacts were few and unsuccessful. Now, researchers at the Institute of Bioengineering and Nanotechnology (IBN) in Singapore are making headway by using a contact lens material that contains a network of nano-sized tunnels that can be filled with photosensitive dyes. The structure of the flexible lens material allows the dye to react quickly and uniformly throughout the lens, according to the researchers.

Edwin Chow, IBN senior research scientist, says this technology has a faster response time than photochromic eyeglass lenses (such as Transitions lenses) currently on the market. While photochromic lenses can take minutes to fully react to light, the new photochromic contacts can respond in 10 to 20 seconds, he says.

Next the research team will test the contact lenses in animals. IBN Director Jackie Ying believes the contacts could be available commercially outside the United States within a year. Approval for use in the U.S. may take longer due to safety testing required by the Food and Drug Administration (FDA).

The study was reported this month in Technology Review, published by the Massachusetts Institute of Technology (MIT).

For the first time in 11 years, Acuvue has released a new brand of multifocal contact lenses for presbyopia, an age-related condition that typically develops at age 40 that causes blurred near vision.

Acuvue Oasys for Presbyopia provides “clear and comfortable vision correction at all distances,” reports manufacturer Vistakon. The contact lenses are designed with improved Stereo Precision Technology optics to provide a smooth prescriptive-power transition for balanced near and distance vision.

The lenses use a “new generation” silicone hydrogel material with Hydraclear Plus, a special wetting agent designed to keep the lenses moist and comfortable for all-day wear. Acuvue Oasys for Presbyopia also blocks more than 96 percent of UVA rays and 99 percent of UVB rays.

It is estimated that 90 million people in the United States will have or develop presbyopia by 2014, creating a high demand for options to deal with their failing near vision. Presbyopes can read more information and get a free trial certificate at www.acuvue.com/presbyopia. A professional exam from an eye doctor is required.