Optometry Research Today is a free monthly online journal that collates and summarizes the latest research about Optometry, including details on myopia, optometric practice, therapy.

Microscopic observations of superficial ultrastructure of unworn siloxane-hydrogel contact lenses by cryo-scanning electron microscopy.

González-Méijome JM, López-Alemany A, Almeida JB, Parafita MA, Refojo MF

Department of Physics (Optometry), School of Sciences, University of Minho, Braga, Portugal. jgmeijome@fisica.uminho.pt

The purpose of this study was to analyze three commercial siloxane-hydrogel contact lens materials, lotrafilcon A, balafilcon A, and galyfilcon A, by cryogenic scanning electron microscopy (cryoSEM). The fully hydrated lenses were frozen in slush liquid nitrogen and qualitatively observed in a cryogenic scanning electron microscope. The superficial ultrastructure of the siloxane-hydrogels was observed at the areas where the lens fractured during sample cryogenic preparation. There are qualitative differences among the three examined materials in the complex polymer network structure existing between the outer layer and the underlying polymer. CryoSEM, although destructive, is a useful tool to investigate the structure of polymers used in contact lenses. This technique allows the observation of the inner structure of polymers in the hydrated state. The ultrastructure, the polymer network underlying the outer surface of siloxane-hydrogels by cryoSEM microscopy, have never been reported before.

Published 9 January 2006 in J Biomed Mater Res B Appl Biomater, 76(2): 419-23.
Full-text of this article is available online (may require subscription).

© 2005-2008 Optometry Research Today. All Rights Reserved.