Jakob Nielsen in his newsletter dated August 19, 2002 has raised the question of font size on web pages.

I have explained on my website, how to increase the font size, either using View - Text Size option or using the button on standard toolbar. You can also choose the bookmark on your links toolbar to increase the font size. Sometimes simply by clicking the stylesheet button on links toolbar increases the font size. You can refer to my Internet Explorer FAQ and Browser utilities section from my website to know more about it. Remember, Internet explorer is a software that needs to be learned like any other software like coreldraw or excel.
Whichever way you like, increase the font size and read. Don't let your eyes suffer because of your ignorance or laziness.