Can't edit page using "visual" only "text" option. Visual appears blank.

Have you tried changing to one of the WordPress default themes; e.g., Twenty Fourteen, Twenty Fifteen, to see if it fixes the problem?

If it does, it may be either some problematic CSS or javascript errors with your current theme.

I had this issue today.

First you need to check this post here – it basically says that it’s a javascript error. https://codex.wordpress.org/Using_Your_Browser_to_Diagnose_JavaScript_Errors

In my case, I found that wasn’t true.

I’ve had this problem before.

Today I had it from a clean install with no add-ons and the default theme.

http://www.michaeltyler.co.uk/install-old-version-wordpress/

Did you try what Michael said above – using your browser to check for JavaScript errors.