Here are some tricks I've found help me to move as far away from the screen as possible:
-Using Enlarge keys. For browsers, these are Ctrl[+] (PC or Cmd[+] (Mac.
-If a web page doesn't display well enlarged, you can copy-and-paste the text into a word processing rogram and enlarge it there.
-Put it all in boldface. That'e easy to do in a word processor. On the web, you can use a "bookmarklet" that makes everything boldface. Here are the simple steps:
1. Make sure your horizontal "bookmarks bar" is showing at the top of your browser. If it isn't, turn it on (it's somewhere in your menu options, probably in the View Menu.)
2. Drag-and-drop this bookmarklet to the left side of your bookmarks bar:
3. Click the "ALL TEXT BOLD" on any web page you visit.
EDIT: The link didn't post correctly due to the mysterioius ways of the forum software, so it can't be dragged-and-dropped. Maybe the moderator will correct it, if not then in a few days I'll create a post on my site where I'm sure it will post correctly.
I think from Windows 8 and higher you can use scaling and some other settings.
I currently set the scaling to 175% using the native 1920x1080 resolution on my 27" screen.
Currently, my face is 140cm (4.5feet) from my screen with these settings.
Another thing you can do on PCs and Macs is use the Magnifier tool. It allows you to zoom in with a keystroke. The magnifier follows the mouse arrow around, if you want. Here are some articles explaining how: