Extended wear contact lenses typically have a Dk/l value that is:

Extended wear contact lenses are designed for prolonged use, often allowing wear for several days or even weeks without removal. The Dk/l value, which represents the oxygen permeability of the lens material in relation to its thickness, plays a critical role in maintaining corneal health during extended wear. A higher Dk/l value indicates that the lenses allow more oxygen to pass through to the cornea, which is crucial for preventing hypoxia (a deficiency in the amount of oxygen reaching the tissues).

Compared to conventional lenses, which might be designed for daily wear and require regular removal for cleaning and oxygen exchange, extended wear lenses generally have a greater Dk/l value. This is because they need to provide adequate oxygen to the eye over longer periods of time, thus improving comfort and safety for those who wear them continuously. The advancement in materials used for extended wear lenses has led to the development of high Dk materials that support longer wearing schedules while minimizing risks. This enhancement in oxygen permeability is essential, promoting better corneal health and reducing the risk of complications associated with contact lens wear.