The chemicals may affect the oxygen transmissibility
factor which allows the corneas to breathe.
For lathe manufactured soft and rigid lenses, practitioners need to decide on which contact lens material is most suitable for any given patient with regard to oxygen transmissibility
and water content.
Issues raised by the NCAC report ranged from lenses being out of specification for base curve or diameter; lenses being too thick and potentially affecting oxygen transmissibility
to pigment found on the surface of lenses; and side effects like corneal swelling.
The high oxygen transmissibility
allows up to five times more oxygen through the lens than traditional soft contact lenses, for white healthy looking eyes," Dr Mahmoud highlighted.
With an oxygen transmissibility
level of 175, Focus NIGHT&DAY extended wear lenses transmit the industry's highest amount of oxygen to the eye's cornea.
They are made of balafilcon A, with revolutionary AerGel(TM) technology for excellent oxygen transmissibility
, and the Performa(TM) surfacing technology that creates a consistent wettable surface for optimal visual acuity and comfort.
The contact lens oxygen transmissibility
(Dk/t) required for no contact lens induced corneal oedema in open-eye and closed-eye conditions is estimated at 35 x [10.
New promotional materials, supported by clinical data previously provided to the FDA, have been developed emphasizing the product's high oxygen transmissibility
, which, among other things, allows for low levels of overnight corneal swelling.
Contact lenses made up of materials with a known Dk, may then have their oxygen transmissibility
calculated, by dividing the oxygen permeability by the thickness of each lens, providing us with Dk/t (units of x [10.
Rapid transition towards silicone hydrogels is principally due to their improved oxygen transmissibility
that allows higher amounts of oxygen to the eye, resulting in better ocular health.
The combination produces a lens with reasonably high oxygen transmissibility
(Dk/t approximately 100), good wettability and resistant to proteins, but very flexible.
The lenses provide high levels of oxygen transmissibility
during wear and are packaged in a moisture rich packaging solution that delivers outstanding comfort on insertion.