Are you stereo blind?
Is your stereovision OK or not? Here under is a simple online test in the form of a black circle you have to focus on and a few lines of text explaining what happens (or should happen).... Have your friends pass the test and learn who is stereoblind among them!
According to several recent studies, between 6 and 12% of the world population are stereoblind. But don't worry too much if you are, there are plenty of depth cues in the world that help you appreciate the depth and distance of objects. And you may as well spare a few bucks when going to the movies...
Ingredients for the receipe : the above black circle displayed on a computer screen some 60 cm (2 feet) from your nose, one finger (yours or not), and both of your eyes!
- Place the finger vertically at half distance between your eyes and the black circle;
- Focus on the circle. What you see should be similar to picture 1 here under;
- Then focus on your finger. What you see should be similar to picture 2 here under.
If you perceive both situations as described, your stereo vision is OK. If not, then you are stereoblind.
In case of bad or absent depth perception,you see only one of the two fingers in the first case and/or one of the two circles in the second case. Sometimes, you just feel a blur change on the silhouette of the finger or the edges of the circle but you don't perceive a really visible difference between both situations. Stereoblindness is not always impossible to cure. In case of doubts, consult an optmetrist.
This test is not a medical one and should not be substituted to a real optometrist test !
If you are interested in stereovision, or look for a list of the perceptual depth cues such as motion parallax, and other physiological aspects of stereoscopic vision, you may as well read chapter 2 of "La Stéréoscopie Numérique" by Benoit Michel. The book is actually available in French and in English (The "Digital Stereoscopy" book is available on Createspace and Amazon - details of the book are available here, including this sample of chapter 2).