Update on lotrafilcon A contact lenses.

Silicone hydrogel contact lenses were introduced in 1999 after polymer chemists were able to successfully copolymerize conventional hydrogel material with silicone polymers, creating a soft material with high oxygen permeability. Comfort has been achieved through surface modifications to improve the wettability of these hydrophobic copolymers. Lotrafilcon A was introduced in 2001 and had the highest oxygen permeability of any of the commercially available silicone hydrogel contact lenses. The popularity of silicone hydrogels has steadily increased since their introduction, and they now account for more than 50% of the soft contact lens market in the USA. The popularity of these contact lenses has been fueled by decades of research implicating relative hypoxia, one of the major complications of conventional hydrogel contact lens wear. The overall complication rate for conventional hydrogel contact lenses is low. However, with 38 million contact lens wearers in the USA, even a low complication rate can result in significant morbidity. Most contact lens-related complications are minor and do not cause visual loss. However, serious complications can occur, and this is particularly true for overnight lens wearers. High-Dk silicone hydrogels, including lotrafilcon A, have reduced complications related to hypoxia. Mechanical complications can still occur, but the rate appears to be low and the risk of microbial keratitis appears to be similar to the rate found with overnight wear of conventional hydrogel lenses. [ABSTRACT FROM AUTHOR]