Is there a standard for indicating a high contrast style?

I am working on a web app and have developed both a normal stylesheet and a secondary high contrast stylesheet. I am coming unstuck when it comes to allowing a user to switch between styles.

Is there a standard icon/text that should be used?

So far I have links as follows (high contrast is only visible in normal view, and normal view is only visible in high contrast).

switch to high contrast switch to normal view