Technical question: help!

Hi

I work for a company whose website has to be used by blind people too. Many internal links have this can of stuff <span class="visuallyhidden u_open_label"> plus a function underneath like "open this window" (in another language).

Problem is that <span class="visuallyhidden u_open_label"> and "open this window" are placed quite often on all the pages of the website, and the main keyword is "open this window", and not the keywords for which many pages have been built for. If I check the keyword density, this happens:

"open this window" has 3 or 4% keyword density
"keyword I want to rank with" has like 1 or 2% density.

My question: beside removing "open this window", is there a way to keep "open this window" several times on each pages, but modify something in the code SO THAT GOOGLE CANNOT SEE THEM, and so they dont impact the keyword density ?

Thank you in advance for your help guys!

You could use an image with the text "open this window" and no background (.png) so that Google doesn't read the text in it.
You can still add class to your img tag if you need it to trigger the function.
Should do the trick