The 2010 Winter Olympics are here, so it’s a good time to compare the performance of contact lens wearers in the United States and Canada.

In a study published recently in Optometry & Vision Science (official journal of the American Academy of Optometry), researchers evaluated the types of contact lenses prescribed in the two countries and how frequently lens wearers replaced their lenses.

A total of 8,400 patient surveys were sent to 420 eye care practitioners in the U.S. and Canada, and 2,232 eligible surveys were completed and returned by 216 practitioners (74 percent U.S., 26 percent Canada).

Results from the surveys revealed:

• 18 percent of contact lens wearers in Canada and 16 percent in the United States wear daily disposable contact lenses.
• 35 percent of contact lens wearers in Canada and 45 percent in the U.S. wear silicone hydrogel contact lenses designed for 2-week replacement.
• 47 percent of contact lens wearers in Canada and 39 percent in the U.S. wear silicone hydrogel contacts designed for monthly replacement.

The degree of noncompliance with recommended lens replacement frequency was essentially the same for contact lens wearers in both countries:

• The lowest noncompliance rates were among wearers of daily disposable contacts (13 percent Canada, 12 percent U.S.).
• The highest were for silicone hydrogel lenses designed for 2-week replacement (50 percent Canada, 52 percent U.S.).
• Noncompliance rates for contact lenses designed for monthly replacement were 33 percent in Canada and 28 percent in the United States.

The primary reason contact lens wearers gave for not replacing 2-week and 1-month lenses according to the recommended replacement schedule was “forgetting which day to replace lenses” (54 percent Canada, 53 percent U.S.).

The primary reason wearers gave for not replacing daily disposable lenses after a single day of use was “to save money” (56 percent Canada, 29 percent U.S.).

SOURCE:  Compliance with contact lens replacement in Canada and the United States. Optometry & Vision Science. December 2009.

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.

A study published in a recent issue of Eye & Contact Lens indicates that children ages 8 to 12 are able to successfully wear daily disposable contacts and that most children in the study preferred wearing contact lenses to wearing eyeglasses.

The three-month study was conducted in Singapore, following a protocol similar to the recent Contact Lenses in Pediatrics (CLIP) study in the United States that found similar results among teenagers.

Participants in the study were fit with 1-Day Acuvue and 1-Day Acuvue for Astigmatism disposable contacts. All children were nearsighted (with or without astigmatism) and had not worn contact lenses prior to the study.

Of the 59 children enrolled, 53 (90 percent) completed the study successfully. At the end of the three-month study period, most of the children and their parents reported preferring the contact lenses to eyeglasses for a variety of reasons, including vision, comfort and appearance.

No eye infections occurred during the study, and the only adverse event noted was the development of a chalazion in one child’s eyelid.

(Many eye doctors recommend daily disposable contacts for children who want to wear contact lenses because the single-use lenses eliminate the need for daily lens care and contact lens solutions.)

Eye & Contact Lens is the official journal of the Contact Lens Association of Ophthalmologists.