To aid in the reading of text for the visually impaired, you can add a magnifying glass, of any size to your site.

You can also get rid of it at any time, and get it back again with a double left click.
You can also view images in as great a degree of detail as the image resolution will allow.

You can even personalise the effect with your own header.
It works without the need for plug-ins because it uses DHTML programming to create the effect.