A novel method to measure oxygen permeability and transmissibility of contact lenses.
OBJECTIVE
The present paper describes an accurate and cost-effective method requiring simple equipment to measure the oxygen permeability and transmissibility of contact lenses.


METHODS
The method involves accurate measurement of oxygen across the material by allowing the gas (oxygen) to pass through the lens material in a specially fabricated lens mould. The expelled gas is collected by dissolution in ethanol and the oxygen is measured by titration of the solvent.


RESULTS
This method is suitable for the measurement of oxygen permeability and transmissibility of contact lenses of varying thickness and different radii of curvature. It can measure Dk and Dk/t of collagen bandage lenses in both wet and dry conditions.


CONCLUSIONS
The oxygen permeability and transmissibility values obtained by this method were compared with the oxygen permeability standard values of commercially available contact lenses and the results are summarised.
Hadassah
J
J
Bioproducts Laboratory, Central Leather Research Institute, Adyar, Chennai, India.
Sehgal
P K
PK
D003261:Contact Lenses; D006801:Humans; D066298:In Vitro Techniques; D010100:Oxygen / Q000737:chemistry*; D010539:Permeability; D015203:Reproducibility of Results
D010100:Oxygen