The Vision Test app - available for iOS devices (and a similar app available for Android devices listed below) - tests Visual Acuity, Astigmatism, Duochrome, Color and far field vision tests. It also includes eye advice and facts and an eye quiz. Note that this app does not replace seeing an eye doctor! However, this app may be beneficial for TVIs, COMS and families to better understand a student's unique visual issues and to help prepare a student for a trip to an eye specialist.
Download Vision Test for iOS.
For a similar app on Android, download Eye Test - Eye Exam