Silicone hydrogel contact lenses are named for the materials used to make these lenses. As with many things, contact lenses have progressed as people develop better technology and materials.
But how exactly do different silicone hydrogels make contact lenses better? We walk through what they are and how they make a difference.
What are silicone hydrogel contact lenses?
Soft contact lenses were made possible in the 1960s and 1970s by the development of water-loving polymers: large molecules made of repeated pieces (think of a long train of many railcars). These were called 'hydrophilic gels' or simply 'hydrogels.'
Silicone hydrogels are the latest in a line of developments aimed at increasing the oxygen permeability (increased comfort, longer wear and better eye health), wettability (better comfort) and clinical performance of contact lenses. Silicone has higher oxygen permeability, allowing more oxygen to pass, than water, so oxygen permeability is no longer tied to how much water is in each lens.
Types of silicone hydrogels
There are many types, even generations, of silicone hydrogels used to manufacture contact lenses today. These come with technical names such as galyfilcon, senofilcon, comfilcon and enfilcon.
Each contact lens, whatever the material, is government agency-approved or cleared for specific wear and replacement conditions. While silicone hydrogels generally improve comfort and allow longer wear, check with your optician about which contact lenses are right for you.
Benefits of silicone hydrogel lenses
The primary benefit of silicone hydrogel lenses is that they reduce the tradeoff between oxygen permeability and wettability. This opens up many possibilities for silicone hydrogel contact lenses, including:
- Extended wear (sometimes for up to six straight nights and days)
- Continuous wear (sometimes for up to thirty days before replacement)
- Increased comfort and performance
Choosing silicone hydrogels
There are many different types of silicone hydrogel materials that are each used to make contact lenses that address different corrective and wearing needs. So, while knowing the benefits of silicone hydrogels can help inform your preferences, you should choose right contact lenses for you by consulting your optician.
Remember that while it might be cheap to buy contact lenses online, some online lenses may not be approved or cleared by the government. All contact lenses should be prescribed for you by your optician, and fitted for your eyes.