If you spend a lot of time reading online, like me then eye strain is probably your biggest complaint. You can stop worrying, because there's a beautiful tool called Readable.
No, don't worry it's free and does not need any installation. All you have to do is drag a link and drop it on to your Browser's Bookmarks Toolbar.
It turns this .....
into this...! It's the same web page, just the style has changed. Beautiful isn't it? You can revert back to the original by just clicking the page.
You can use the theme I use - just drag and drop this link into your Bookmarks and when you are on any web page just click this Readable bookmark. Or you can make one yourself. Here's the actual site with a tutorial - Readable theme setup.