Optometric tests of relief vision

Fly stereotest

The fly test (or Wirt's Stereotest) is an optometric test of relief vision. It is one of the most common tests to check for peripheral stereoscopy, especially in children.

It is made up of two plates of polarized images to look at with the glasses provided: on the right the test plate of the fly and on the left the test plate of Wirth comprises a series of symbols spread over three lines of which only one is in relief on each line. It also includes a series of squares each comprising 4 circles, one of which must be perceived in relief

Butterfly stereotest

The stereo butterfly test is composed like the fly but with a butterfly image on the right. It enables relief perception for both gross stereopsis and fine depth perception.