Evaluation of Hydrous Lenses Using SPM

Introduction

We performed comprehensive evaluations of hydrous lenses as typified by contact lenses using a scanning probe microscope (SPM). To improve their performance, various types of surface treatment are applied to hydrous lenses. However, limited analysis methods are available to evaluate the lenses under conditions close to actual use. The SPM permits observations in a liquid and can measure both the surface shape and the surface properties. Thus, it is widely used for the measurement of biological samples and hydrophilic polymers. We used a Shimadzu SPM-9700 to perform the following measurements on two types of hydrous lenses in artificial tears, in an environment close to actual use: 1. observation of surface shape and phase image, 2. evaluation of hardness, 3. measurement of friction coefficient, and 4. imaging of surface potential distribution in air.

May 22, 2013 GMT