Hostname: page-component-586b7cd67f-gb8f7 Total loading time: 0 Render date: 2024-11-23T14:45:29.622Z Has data issue: false hasContentIssue false
  • English
  • Français

Quality Control of Silicone Hydrogel Contact Lenses by Impedance Spectroscopy

Published online by Cambridge University Press:  20 February 2014

M. Torres  and
K.S.V. Santhanam
M. Torres
Affiliation:
Bausch & Lomb, Rochester, NY 14609 Center For Materials Science and Engineering and School of Chemistry and Materials Science, Rochester Institute of Technology, Rochester, NY 14623
K.S.V. Santhanam
Affiliation:
Center For Materials Science and Engineering and School of Chemistry and Materials Science, Rochester Institute of Technology, Rochester, NY 14623
Get access

Abstract

We wish to propose an impedance spectroscopic method for the quality control of contact lenses by measuring the pore resistance. Silicone hydrogels are excellent materials for use as contact lenses and their on eye performance is dependent on salt intrusion characteristics which are related to the pore resistance and water uptake. When the contact lenses are placed on the eye, they are expected to permeate ions and molecules to maintain ocular health. The hydrogel pores control the permeability and can be viewed as a quality control parameter. Two models are considered here: in one, the contact lenses are considered as strong rigid films with no permeability. In another, the hydrogels are having ionic permeability. We designed a silicone hydrogel contact lens attachment holder that is amenable for electrochemical impedance measurements. The electrochemical impedance measurements were carried out in an inert medium of 0.1 M Na2SO4. The impedance measurement experimental parameters used were a) AC potential 10 mV rms b) frequency range 0.1-210 kHz and c) open circuit potential of 0.207 V. The impedance variation with frequency was constructed for a number of hydrogels. The ideally acceptable silicone hydrogel contact lenses showed an impedance change with frequency in a sigmoidal fashion with a characteristic phase angle (acceptable in the range of 70-75o). The hydrogel pore resistances for the acceptable contact lenses are in the range of 4.5-11 kΩ. When the impedance showed a linear decrease or no well defined phase angle, the contact lens is considered acting as an insulator-a test for rejection. A test of the model was done with several acceptable contact lenses in the market. This study revealed interesting aspects of the influence of pulsating electric field on the silicone hydrogels.

Keywords

biomaterialbiomedicalelectrical properties
Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 1626: Symposium K – Micro- and Nanoscale Processing of Materials for Biomedical Devices , 2014 , mrsf13-1626-k08-18
Copyright
Copyright © Materials Research Society 2014 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Arroyo, R., Crespo, D., and Alonso, J., Optom Vis Sci. 90(3), 282 (2013).CrossRefGoogle Scholar
Yuen, G.S., Chou, B.R., Ngo, T.P., Cheng, B.B., and Dain, S.J., Clin Exp Optom. 94(4), 341 (2011).CrossRefGoogle Scholar
Rebsamen, M., Boucheix, J.M., and Fayol, M., Appl Ergon. 41(1),150 (2010).CrossRefGoogle Scholar
Alonso-Caneiro, D., Iskander, D.R., and Collins, M.J., Eye Contact Lens. 35(5), 227 (2009).CrossRefGoogle Scholar
Forister, J.F., Forister, E.F., Yeung, K.K., Ye, P., Chung, M.Y., Tsui, A., and Weissman, B.A., Eye Contact lens, 35(4), 176 (2009).CrossRefGoogle Scholar
Papas, E., Dahms, A., Carnt, N., Tahhan, N., and Ehrmann, K., Optom Vis Sci. 86(4), 318 (2009).CrossRefGoogle Scholar
Cho P, P., Cheng, S.Y., Chan, W.Y., and Yip, W.K., Ophthalmic Physiol Opt. 29(1), 49 (2009).CrossRefGoogle Scholar
Samadi, M., Rahmani, A., Sedehi, M., and Sonboli, N., J Res Health Sci. 28, 25 (2009).Google Scholar
Forister, J.F., Chao, J., Khy, K., Forister, E., and Weissman, B.A., Cont Lens Anterior Eye. 31(5), 228 (2008).CrossRefGoogle Scholar
Seibel, E.J., Trilsch, W.R., and Lee, D., Am J Optom Physiol Opt. 65(4), 298 (1988).CrossRefGoogle Scholar
Pearson, R.M., Clin Exp Optom. 91(4), 379 (2008).CrossRefGoogle Scholar
Tan, J., Papas, E., Carnt, N., Jalbert, I., Skotnitsky, C., Shiobara, M., Lum, E., and Holden, B., Optom Vis Sci. 84(5), 422 (2007).CrossRefGoogle Scholar
Nicholson, P.C. and Vogt, J., Biomaterials, 22, 3273 (2001).CrossRefGoogle Scholar
Jones, L., Subbaraman, L., Rogers, R. and Dumbelton, K., Optician, 232, 6067 (2006).Google Scholar
Peng, C.C. and Chauhan, A., Journal of Membrane Science, 399, 95 ( 2012).CrossRefGoogle Scholar
Huff, J.W., Invest Ophthalmol Vis Sci. 31(7), 1288 (1990).Google Scholar
Bonanno, J. A., Progress in Retinal and Eye Research 22, 69 ((2003).CrossRefGoogle Scholar
Weikart, C.M., Matsuzawa, Y., Winterton, L., and Yasuda, H.K., J. Biomedical Materials Research, 54, 597 (2001)3.0.CO;2-S>CrossRefGoogle Scholar
http://www.gamry.com/application-notes/eis-of-organic-coatings-and-paints Google Scholar