High-index lenses aren’t just for eyeglasses anymore. New high-index gas permeable (GP) contact lens materials now make GP contacts thinner and lighter, especially for people with high prescription powers.

Like high-index eyeglass lenses, high-index gas permeable contacts bend (refract) light more efficiently, so less lens material is needed for a given prescription power.

In the June 2010 issue of Contact Lens Spectrum, Ronald K. Watanabe, OD, associate professor of optometry at New England College of Optometry, outlines the benefits of high-index GP contacts. These include:

• Because high-index lenses are thinner than regular GP lenses, they fit more easily under the upper eyelid, which can improve comfort, especially in cases of high myopia.

• High-index GP lenses also are lighter, which can improve the upper eyelid’s ability to hold them properly in place on the eye.

• High-index materials also can increase the effective “add” power of aspheric GP multifocal contacts, potentially providing a better correction of presbyopia for contact lens wearers over age 40.

On the downside, high-index gas permeable contacts may not stay as moist as conventional GP lenses, possibly making them less comfortable for someone with dry eyes.

Also, high-index lenses have a lower oxygen permeability than some other GP lenses, which may be a problem for wearers whose corneas cannot tolerate a reduced oxygen supply, according to Dr. Watanabe.

Many contact lens wearers fail to replace their lenses on time, don’t remember the name of their contact lens solutions and don’t replace their contact lens storage case when it gets old and dirty.

These are some of the findings of a new study conducted by researchers at the Centre for Contact Lens Research (CCLR) at the University of Waterloo (Ontario, Canada).

A total of 158 U.S. eye care practitioners assisted in the study by distributing surveys to their contact lens patients. A total of 1,654 of the returned patient surveys were eligible for analysis.

The mean age of contact lens wearers in the study was 34 years (range: 14 to 79 years). The majority wore their lenses on a daily wear basis, but 12 percent reported wearing extended wear contact lenses on a continuous basis.

Among the results of the study:

• 16 percent of participants wore daily disposable contacts; 45 percent wore 2-week replacement silicone hydrogel contact lenses; 39 percent wore 1-month replacement silicone hydrogel lenses.

• 20 percent of participants were unsure of the type of contact lenses they were wearing.

• 52 percent of those wearing 2-week disposable contact lenses, 28 percent of those wearing 1-month replacement lenses and 12 percent of those wearing daily disposable lenses did not replace their contacts on a timely basis.

• The overall rate of patient noncompliance with the replacement frequency recommended by their eye doctor was 38 percent.

• When asked about their lens care regimen, 40 percent could not recall or did not know the name of their contact lens care products.

Generally, contact lens cases should be replaced at least every 3 months, but only 50 percent of the study participants reported doing so. A total of 20 percent reported replacing their case every 6 months, 16 percent said they replaced their case annually and 14 precent aid they had never replaced their lens storage case.

The researchers also found that end-of-day contact lens discomfort was reported by a higher proportion of contact lens wearers (51 percent) who failed to replace their contact lenses on time.

A full report of the study appears in the June 2010 issue of Contact Lens Spectrum.

Marietta Vision (Marietta, Ga.) recently announced the launch of the company’s new Bio Contact Lens.

The new soft contact lenses are made of a combination of hydrogel polymers that provides unsurpassed performance for dry eyes, according to the company. Bio Contact Lenses also are highly biocompatible and are a more natural alternative to other contact lens materials, the company says.

Other desirable properties of Bio Contact Lenses listed by Marietta Vision include greater surface wettability and resistance to dehydration for increased wearing time and better end-of-day wearing comfort.

The new lenses also feature advanced aspheric optics designed with wavefront technology, making them capable of reducing higher-order aberrations and producing sharper vision and better contrast sensitivity, especially at night and in other low-light conditions, the company says.

Bio Contact Lenses correct both nearsightedness and farsightedness and have a light blue handling tint. They are available only through private eye care practitioners, and are not sold online or at large chain optical stores or discount stores.

Need another reason to quit smoking? How about because it might make your contact lenses feel better and decrease your risk of eye problems?

Researchers at Case Western Reserve University (Cleveland, Ohio) recently fit 205 patients with CIBA Vision’s Night & Day silicone hydrogel contact lenses for continuous wear and followed them for a period of one year. The purpose of the study was to identify risk factors associated with the development of corneal infiltrates during extended wear of the lenses.

Corneal infiltrates are small, hazy, gray-appearing areas that appear in the clear front surface of the eye (cornea) as evidence of inflammation. They are composed of inflammatory cells such as white blood cells, and typically appear in the periphery of the cornea, often under the upper eyelid.

Symptoms of corneal infiltrates include a foreign body sensation (feeling something is “in” the eye), red eyes, excessive tearing, sensitivity to light and contact lens discomfort.

The researchers found that smokers who wore the Night & Day contact lenses on a continuous basis had greater than four times the risk of developing corneal infiltrates, compared with non-smokers.

Treatment options for corneal infiltrates include discontinuing contact lens wear, use of topical antibiotics (to treat or reduce the risk of infiltrate-associated eye infections) and/or use of topical anti-inflammatory medications.

A full report of the study was published on the Investigative Ophthalmology & Visual Science website on June 10, 2010.