High Tech Contact Lenses? Part 2

Posted by Harvard Sylvan, OD on Tuesday, April 6, 2010

What do stents, catheters, and contact lenses have in common?  As one is metal, one is rubber and one is made from a combination of water and plastic, there wouldn’t appear to be any similarities.  So, what exactly do they have in common?  To perform properly, they all need protection from protein deposits.  Stents and catheters need protection against proteins found in blood plasma and contact lenses need protection from deposits formed by protein in tears.

There are two things to which all contact lens wearers can relate – dryness and discomfort due to deposits on lenses and lenses becoming dryer as the day progresses.  Fortunately, there is a contact lens material that is very resistant to both protein deposits (the most common type) and dehydration.   The material is PC hydrogel and CooperVision’s PC hydrogel material is the only one that has FDA clearance to be labeled as ‘may provide improved comfort for contact lens wearers who experience mild discomfort or symptoms relating to dryness during lens wear (non-Sjorgen’s only)’.

Interestingly, this material was not developed by a contact lens company, it was created by a biotech company that was looking to develop a material that was very resistant to protein deposits for devices associated with cardiology (stents, catheters, guide wires, etc.).  Those devices come into contact with blood plasma which contains a significantly higher amount of protein than do tears.  A material was created by incorporating PhosphorylCholine (hence ‘PC’) which is a part of the human cell membrane.  Protein does not stick to our cells in part because of PC.  When incorporated into these medical devices there was a significant reduction in the amount of protein deposits that formed.  The biotech company started looking for other objects that needed protection from protein deposits and realized that contact lenses were an ideal choice.  A new material was developed that incorporated PC and was called PC hydrogel.

Not only did PC hydrogel lenses have excellent resistance to protein deposits, the lenses were found to be very resistant to drying out.  Although this was not why the material was developed, it has become the main advantage.  

PC hydrogel lenses are available for virtually every vision correction.  Even with the increasing popularity of silicone hydrogel lenses, PC hydrogel lenses are still a viable, and often preferred, option.  The material is unique because it attracts and binds water to keep lenses moist all day, translating into long wearing comfort for you. 

PC hydrogel lenses are not approved for overnight wear.  If you do not plan on sleeping with your lenses on and want a lens that does not dry out easily, has minimal deposits and provides long wearing comfort each day, ask your eye care provider for lenses made with PC hydrogel material, such as the line of Proclear lenses from CooperVision. Welcome to the biotech world!

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