Opinions on the best material for eyes?

I was wondering what the preference was for the see-through part of the eyes were.

I've tried aida cloth because it held paint in, however I've found that even when I poked a hole through EVERY weave to open them up more, the visibility is still sub-par.

I don't have much experience with buckram but I've heard people don't always like it because of visibility or paint issues.

So is there a better alternative? I was hoping to find something that holds paint in well but has good visibility.