Silicone Hydrogel Lenses

Silicone hydrogel has long been known to transmit more oxygen than almost any other material known. Unfortunately it is inherently dry, and so developing a suitable soft silicone hydrogel lens material was always challenging. Early attempts partially succeeded by altering the surface of the lenses, but when they were fitted, problems with the surfaces breaking down meant that they were abandoned.

Eventually the problems were overcome and slowly silicone hydrogel lenses began to enter the market. Initially several of the lenses were marketed as "extended-wear", to be left in the eye continually for up to one month at a time. Some practitioners embraced the idea and many wearers do indeed wear these lenses for long periods. However, there was some resistance to the extended wear modality and the higher rate of complications meant that the extended wear concept only achieved about 8% success within the market.

The main success of these new lenses is in daily wear. Practitioners and patients readily accept the concept of having more oxygen available than the eye requires.

Patients can enjoy longer periods of wear without the worry of complications caused by oxygen deprivation and practitioners know that they can safely allow their patients to enjoy the long periods of wear they demand - even occasional overnight wear at weekends or when travelling can be done without the problems associated with previous lenses.

Silicone hydrogel lenses are available from most major manufacturers, and are rapidly taking over from the traditional soft materials. Special lenses can also be supplied to patients with unusual prescriptions or whose eye-shapes fall outside the range of off-the-shelf products.

Silicone hydrogel has another distinct advantage over soft lens materials in that it does not dry out during wear. Many patients find that they can now achieve all-day wear compared to their soft hydrogel lenses, which would dry out after 6-8 hours.