Testing your vision by reading tiny letters on a distant wall chart could become a thing of the past thanks to a revolutionary gadget.

The Personal Vision Tracker (PVT) is a US$29.99 device invented by California-based firm EyeQue and can tell users if they need glasses from the comfort of their armchair.

A microscope accessory attaches to a smartphone to complete the test and connects to the EyeQue smartphone app which also tracks the user’s results.

It performs a 15-minute-long test to determine the quality of a person’s sight. It then provides guidance on which glasses to purchase.

The app tests the user’s eyesight using a red and green line that they view through the microscope.

Users tap the buttons on the smartphone to move the two lines together until they overlap and form a yellow line. The amount of movement needed to get the lines to completely overlap calculate the strength of the user’s eyes.

The user then rotates the microscope to move on to the remaining eight tests.

Results from the test are provided using the same spherical*, cylindrical* and axis numbers that are used in a standard eyeglasses prescription. The user can enter these figures online and purchase the required glasses.(SD-Agencies)