Oxygen permeability of disposable soft contact lenses

Disposable contact lenses are inexpensive hydrogel lenses that are approved for both daily and extended wear. Confusion may exist regarding the physical properties of disposable contact lenses. We used the single-chamber polarographic oxygen permeability measurement method, corrected for both boundary and edge effects, to determine objectively the oxygen permeability of three brands of disposable contact lenses. The oxygen permeability values determined for each lens material are as follows: Acuvue, 18 x 10(-11) cm2 ml O2/sec ml mm Hg (Dk); NewVues, 15 x 10(-11) Dk; and SeeQuence, 9 x 10(-11) Dk. This demonstrates that the inexpensive production techniques, which confer a relatively low unit expense, do not change the physical properties of the hydrogel materials as they relate to oxygen permeability and transmissibility. We concluded that hypoxic stress to the cornea is just as likely when using a disposable contact lens as it is when using a conventional reusable soft hydrogel lens of similar composition and water content.