Oxygen Permeation Measurement for Contact Lens
Recently, the first professional contact lens oxygen permeation instrument has been launched by Labthink. Oxygen permeation Instrument complies to the related ISO standards completely, and the test results are very ideal.
It is well known that the level of oxygen permeation of contact lens will affect the level of the comfort that they provide for the wearers, and then it would have an impact on contact lens’ sale, therefore, the contact lens oxygen permeation test of attracts the most attention from the contact lens manufacturers. Meanwhile ISO also constituted the relevant testing standards for the oxygen permeation test of contact lens: ISO 9913-1 Optics and optical instruments — Contact lens.
The test principle and test equipment stipulated by ISO 9913-2 are close to the coulometric method used by oxygen permeation test of flex packaging materials. The mounted sample divides the cell into test gas cell and carrier gas cell. The test gas passes through the sample into the carrier gas cell and is carried by the carrier gas to the sensor. The sensor detects the amount of the test gas passed.
From the above principle, the oxygen permeation test of contact lens and flexible packaging materials are approximately divided into the following steps: zero point test for system, fill oxygen into test chamber, output value of sensor goes steady (judge penetration equilibrium), get test results.
Before formal tests, the oxygen permeation test equipment needs to be calibrated with reference film. The ISO 9913-2 standard clearly pointed out the sample used for calibration: SRM1470, this film is exactly same with the reference film used in ASTM D 3985 standards. So it also proves that the comparability between oxygen permeation test of contact lens and flexible packaging material.
However, there are also some differences between the test of contact lens and flex packaging materials, that are mainly divided into two points:
Firstly, the fixture of sample is different; mainly on the shape and area of samples.
Secondly, test environment is different, the standard temperature of film oxygen permeation test is 23℃, whereas, in order to simulate the actual human use, the test temperature of contact lens ought to be 35℃. Meanwhile, the temperature change will affect test result observably, therefore, the stability of temperature is very important during test.
Labthink designed and manufactured clamps accessories, temperature controller settings specially for the contact lens test based on the existing, Oxygen Permeation Tester, the professional oxygen permeation tester of flexible packaging materials. Not only is the special shape of the samples considered, but also the special test environment is simulated.Further details please feel free to contact Shirley via firstname.lastname@example.org or (tel)0086-531-85811021 at Labthink.
Labthink is a professional manufacturer of testing equipments for packaging industry. Labthink focus on research and development of the packaging materials’ permeation properties test technique.