Copy of Contact Lens Specification

CONTACT LENS SPECIFICATION

Water Content 

• What is meant by water content? 

• In order for contact lenses to keep its shape and function properly, it needs to reach a certain percentage of water content. Some contact lenses have low water content, while others have higher water content. Low water content in contact lenses are more comfortable to use for longer periods of time, although with lower levels of oxygen permeability (Dk) . On the contrary, high water content in lenses tend to be most comfortable only in its early hours of wear, but it is advantageous in its higher levels of oxygen permeability.  

 

Diameter 

• What about diameter? What’s the difference with graphic diameter? 

• The diameter is the total diameter of a lens, including its transparent part 
• The graphic diameter is only the patterned part of a lens, which excludes the transparent outer part. 

 

Base Curve 

• What is a Base Curve (BC)? 

• This refers to the curvature behind your lens, which will sit on your eye. 

 

Expiration 

• What does the expiration date on the bottle/vial mean? 

• The lenses themselves can't actually expire; it's the saline solution in the blister pack that does.
• During the manufacturing of contact lenses, each lens gets sterilized and packed in an air-tight vial along with saline solution.
• Beyond that date, the active ingredients within the saline solution can lose their form, becoming acidic or more alkaline and in turn, damaging the lens.

• How long until you should dispose your lens? 

• Each vial/botol will state the months disposable, usually it varies from 1-6 months.