Silicone Hydrogel Contact Lenses
For Extended Wear
Materials with high Dk values and greater oxygen permeability for continuous or extended wear contact lenses brought the biggest changes in 2003.

Lotrafilcon A, which is used in CIBA Vision's Focus NIGHT & DAY' soft lens, received FDA approval in October 2001. These lenses are approved for daily wear up to 30-day extended wear.

Of the many types of new contact lenses for extended wear, most bring only a small advancement in ease of fitting or patient satisfaction. It's not often that ophthalmologists, optometrists, contact lens fitters, and opticians become unanimously excited about a new contact lens for extended wear. Now this has all changed. The impact of high-DK, high-oxygen permeable silicone hydrogel lenses on the ophthalmic community has been revolutionary and represents the most significant contact lens trend in 2003.

Impact on Contact Lenses for Extended Wear

In the 1980's, the first extended wear contact lenses were gaining popularity. But within a few years noted clinicians were warning of the adverse effects of wearing lenses for extended periods. The FDA responded to the mounting evidence by backing away from the 30-day approval of contact lenses for extended wear, instead recommending a maximum continuous wearing time of one to two weeks. Finally, in 2001, in an action that surprised many ophthalmic professionals, the FDA reversed itself and granted a new material with high-DK values—silicone hydrogel—approval for 30 days of continuous wear. This move represented a dramatic change in the FDA's position on contact lenses for extended wear.

Who Offers Them?

"The impact of high-DK, high-oxygen permeable silicone hydrogel lenses on the ophthalmic community has been revolutionary and represents the most significant contact lens trend in 2003."

The FDA approved a new material, Lotrafilcon A, which is used in CIBA^® Vision's FOCUS^® Night & Day™ soft lens, for extended wear use in October 2001. These lenses are approved for daily wear up to 30-day extended wear, and are available for multifocal, myopia, hyperopia, and toric lens fitting. In November 2001 a similar material, Balafilcon A, used in the PureVision™ lens from Bausch & Lomb, Inc., received FDA approval for continuous wear up to 30 days. It was approved for monovision, myopia, hyperopia, and astigmatism in phakic and aphakic patients. The Bausch & Lomb lenses were subsequently removed from the United States market because of issues regarding patent infringement, although the PureVision lenses are still available in Canada and many European countries.

Barriers Broken

The fitting and wearing of extended wear contact lenses has always presented challenges. Crisp visual acuity requires a clear healthy cornea with an intact epithelium. An interrupted corneal epithelium puts the cornea at risk of decreased vision and potential infection. Over-wear syndrome, that is, corneal edema caused by hypoxia, can produce or accompany a corneal epithelial defect. Central corneal hypoxia may cause neovascularization of the limbal area, and the breakdown of the epithelium could lead to microbial keratitis and/or sterile infiltrates into the cornea.

ACUVUE® ADVANCE™ with HYDRACLEAR™, though not yet approved for extended wear, is another popular silicone hydrogel based lens.

Silicone-hydrogel lenses have now removed these obstacles to healthy use of contact lenses for extended wear. Their high-DK values provide the best oxygenation for the cornea, relieving those common problems. The new contact lenses also appear to resist protein build up more effectively. The lens surface works to deter bacteria adhesion, which contributes to a decreased chance of microbial infection.

Silicone-hydrogel materials bring both doctor and patient new opportunities in contact lenses for extended wear, for a greater number of wearers. The new lenses can be fitted by any vision care specialist prescribing soft contact lenses.