Authors:
Chih-Wei Hung
1
;
Kuo-Cheng Huang
1
;
Hsin-Yi Tsai
1
;
Yu-Hsuan Lin
1
and
Patrick Joi-Tsang Shum
2
Affiliations:
1
Instrument Technology Research Center and National Applied Research Laboratories, Taiwan
;
2
Cathay General Hospital, Taiwan
Keyword(s):
Hydrogel Contact Lens, Oxygen Permeability, Water Content, Dehydration Rate.
Related
Ontology
Subjects/Areas/Topics:
Optics
;
Photonics, Optics and Laser Technology
;
Spectroscopy, Imaging and Metrology
Abstract:
The diffusion coefficient D, gas solubility k of material and the thickness of lens t were used to evaluate the
oxygen permeability Dk/t of contact lenses (CLs). However, the nominal value Dk/t is usually not consistent
with the actual oxygen permeability of wearing CL. As the oxygen travel through the hydrogel, it need to be
carried by water molecules in the lens material; thus, the higher the water content (WC) of the material, the
higher the Dk/t value. In order to obtain the WC and Dk/t of wearing CL, we create a testing platform to
simulate the wearing status of CL. When the light traveled through the lens, we found that the attenuation in
green light is smoother than other wavelengths. Moreover, the WC is higher, its dewatering rate at room
temperature is lower, and the light attenuation is relatively smaller. Comparing with the other CL of similar
WC, the Dk/t of CL is higher if it has higher dehydration. In the study, we evaluated the WC and Dk/t of
hydrogel CL based on the l
ight attenuation in eight minutes. The attenuation degree of light after traveling
through the CL can be used to estimate the Dk/t of hydrogel CL.
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