The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
This is a free app that turns iphone into a magnifier. The unique thing is text enhancement. It replaces your reading glass. Better yet it automatically converts text into black and white so they are easier to read (see screenshots).