Ciba Vision

The concept of silicone hydrogel lenses of the first proposed 20 years ago. The potential benefits are clear, but the technological challenge was as difficult as the need to combine oil and water to produce an optically clear product. research organizations to date has invested significant financial resources and academic achieve high performance soft lenses of today. They did this simply because they see this material as the way forward and the ultimate standard of the future.

At the time of writing, silicone hydrogel lenses are available in the U.S. four manufacturers: "Night & Day" and "O2Optix" CIBA Vision, Pure Vision, Bausch & Lomb, and "Acuvue Oasys" and "Advance" Vision Care of J & J.

Oxygen transport

So, whatac a‚¬ a„c s so special about silicone hydrogel as a material of the lens? Essentially, the great advantage of this material is itac a‚¬ a„c s ability to carry oxygen to the eye and thus maintain proper eye health. The modern technology of contact lenses is everything to do with the permeability of oxygen is measured using the "DK" index. And for optimum transmission of oxygen, it must be as high as possible.

The Dk traditional, non-silicone hydrogel lenses is directly related to the amount of water that may contain material from the dissolved oxygen in the water-component of the material and thus diffuses across the lens. Denmark in fact increases logarithmically with increasing water content. The water itself has a Dk of only 80, putting a cap on the Dk of conventional materials, and the original material soft contact lenses, polyHEMA, possesses a Dk of only around 10 (with a content about 38% water).

However, silicone hydrogels, the relationship between Denmark and the water content is the opposite. Here the water content implies lower Dk higher. With these lenses Dk increases significantly the silicone content - not only water - an increase of the target. The values Dk silicone hydrogel contact lenses are much higher than older soft lens materials.

SLEEPING contact lenses

According to market data from CIBA Vision, 84% of soft contact lens wearers sometimes sleep with their lenses, and third to admit this regularly. 25% of the holders of a two-week disposable lenses low oxygen transmissibility occasionally or regularly sleep in their lenses overnight. And 72% of soft contact lens wearers said they would rather be allowed to wear their lenses during the night he provided was safe.

Thus, the demand for lenses with silicone hydrogel capablities is obviously very high, with nearly three quarters of soft contact lens wearers will be able to sleep in their lenses.

LENS HANDLING

silicone hydrogel lenses are more rigid than their conventional counterparts, due to the presence of silicone. This rigidity does possess some advantages, which makes the lenses much easier to handle and therefore ideal for carriers with a touch less delicate. There is a drawback that, however, the rigidity makes the lenses less likely to adopt the shape of the eye so easily, leading to the possibility of some small comfort.

REDUCED DEPOSIT

Historically, deposits of protein and fat was a problem with contact lenses. The amount of deposits is primarily related to the duration of wear, the lens material and tear composition of each individual user. With traditional lenses, a frequent replacement schedule greatly reduces the buildup of harmful deposits.

silicone hydrogel lenses contacts have proven to offer significant benefits in reducing the protein and lysozyme deposition. Indeed, combined with the correct replacement schedule and appropriate care system, problems associated with protein.