The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
iOcchio is the application that contains optometric tables normally used by eye specialist to measure the vision or visual acuity. Try it yourself to make the visual tests from home, keeping in mind that the use of optometric tables are just guidelines.