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Labthink Instruments Co., Ltd.
Oxygen Transmission Performance for Contact Lenses

Oxygen Transmission Performance for Contact Lenses

Product catalog summary

Introduction
The document discusses the importance of oxygen transmission performance in contact lenses, which affects consumer experience and sales. Testing this performance is crucial for manufacturers.

Standards and Testing Methods
The International Standard Organization (ISO) has established two standards for testing oxygen permeability in contact lenses: ISO 9913-1 and ISO 9913-2. The latter uses a coulometric method similar to that used for flexible packaging materials.

Testing Principle
The sample is placed in a testing chamber divided into two sections. Oxygen is introduced into the upper chamber, while nitrogen flows through the lower chamber to a coulometric sensor. The sensor measures the oxygen quantity in the nitrogen flow to calculate the oxygen transmission rate (OTR).

Testing Procedure
The procedure involves purging the system, introducing oxygen into the upper chamber, stabilizing the sensor output, and obtaining results. Calibration with reference films is necessary, using SRM 1470 as specified in ISO 9913-2.

Differences in Testing
Differences between testing contact lenses and flexible packaging include clamping structures, sample shapes and sizes, and testing environments. Contact lenses are tested at 35℃ to simulate actual usage conditions, unlike the 23℃ standard for films.

Labthink's Contribution
Labthink has developed specialized clamping accessories and temperature control devices for testing contact lenses, based on their OX2/230 Oxygen Transmission Tester for flexible packaging materials. Additional equipment for testing oxygen transmission rate and gas permeability is available on their website.

Catalog excerpts

Oxygen Transmission Performance for Contact Lenses-1

Contact: Yarina Gao Email: [email protected] Phone:086-531-85060139 Oxygen Transmission Performance for Contact Lenses It’s well-known that the oxygen transmission performance of contact lenses would directly influence the feelings and experiences of the consumers, and the sales volume would be affected correspondingly. Therefore, the test for oxygen permeation performance of contact lens has become a main concern of the manufacturers. Owing to the importance of oxygen transmission performance of contact lenses, ISO, International Standard Organization, has formulated two relevant testing standards as follows: ISO 9913-1, Optics and optical instruments—Contact lenses—Part 1: Determination of oxygen permeability and transmissibility with the FATT method; and ISO 9913-2, Optics and optical instruments—Contact lenses—Part 2: Determination of oxygen permeability and transmissibility by the coulometric method . The testing principle and instrument of ISO 9913-2 are similar to those of coulometric method applied in oxygen transmission rate tests for flexible packaging materials. The testing principle is as shown in Fig. 1. Testing principle Place the sample to be tested into the testing chamber, and the chamber would be separated into two sections: upper chamber and lower chamber. Then, testing gas with a certain oxygen concentration is purged into the upper chamber. Carrier gas flow, that is, nitrogen gas flow, purges into the coulometric sensor through the lower chamber. Though the pressures of the upper chamber and the lower chamber are the Contact: Yarina Gao Email: [email protected] Phone:086-531-85060139

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Oxygen Transmission Performance for Contact Lenses-2

Contact: Yarina Gao Email: [email protected] Phone:086-531-85060139 same, the pressures of oxygen differ in them. Thus, oxygen would, with the help of concentration difference, permeate through the sample and into the carrier gas side. Then, oxygen would be taken to the coulometric sensor. The sensor would precisely measure the oxygen quantity in the carrier gas flow (that is, nitrogen gas flow), and calculate the oxygen transmission rate (OTR). It can be concluded, from the above-mentioned principle, that oxygen transmission performance tests for contact lenses and flexible packaging materials...

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Oxygen Transmission Performance for Contact Lenses-3

Contact: Yarina Gao Email: [email protected] Phone:086-531-85060139 clamping accessories and temperature control device for oxygen transmission tests of contact lenses. Labthink also has some other equipments that can be used to test the Oxygen Transmission Rate or Gas permeability Test Please go to our website for more details about our products. Contact: Yarina Gao Email: [email protected] Phone:086-531-85060139

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