This mHealth application intent is to provide and empower mobile regular users and health professionals with the tool with which they can estimate their or others visual acuity, based on a classical Snellen Chart Test. This App is innovative because it transforms an old style poster test design in a new, modern, intuitive, ubiquitous test. One App with a simple user interface, and an intuitive navigation chart using swipe gestures to navigate from optotype to optotype, and with the capability to adapt the Snellen Chart Test to different screen sizes, screen resolutions and user distances.