Tsutomu Goshima

The effect of polymer structure on durability of high dk rigid gas-permeable materials*

Abstract To clarify the issues of fragility of and deposition on high Dk rigid gas-permeable (RGP) materials, some physical properties,i. e., impact strength, flexural strength, and the materials physical microstructure, were evaluated for different RGP lenses. No correlation was found between the breakage strength and Dk of the material. The main factor that determined breakage strength was found to be the physical microstructure of the RGP material. However, by combining the results of the impact and flexural strength tests, we can adequately predict the level of lens breakage found in clinical studies. The effectiveness of the polymer alloy’ type of physical microstructure of RGP materials in resisting deposits is also considered.