Jump to content

Vergence-accommodation conflict: Difference between revisions

Jason VR (talk | contribs)
change links
No edit summary
 
(7 intermediate revisions by 3 users not shown)
Line 1: Line 1:
'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object ([https://en.wikipedia.org/wiki/Vergence vergence]), and the focusing distance ([https://en.wikipedia.org/wiki/Accommodation_(eye) accomodation]) required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.
{{stub}}
[[File:Vergence accommodation conflict image.png|thumb|right|250px|Vergence-accommodation conflict in VR compared to real-world vision]]
A '''vergence-accommodation conflict''' ('''VAC'''), also known as an '''accommodation-vergence conflict''', is a phenomenon in the human visual system that occurs if the brain receives mismatching cues between [[vergence]] and [[Accommodation (eye)|accommodation of the eye]]. This commonly occurs in [[virtual reality]] devices, [[augmented reality]] devices, and binocular flat focus autostereoscopic displays. The effect can be unpleasant and cause eye strain.


It can contribute to focusing problems, visual fatigue, and eyestrain, while looking at stereoscopic imagery, and vision effects that linger even after ceasing looking at the imagery.
It can contribute to focusing problems, visual fatigue, and eyestrain, while looking at stereoscopic imagery, and vision effects that linger even after ceasing looking at the imagery.
Line 8: Line 10:
The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are not close to the viewer.
The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are not close to the viewer.


The problem occurs because our eyes have evolved an [https://en.wikipedia.org/wiki/Accommodation_reflex accommodation-vergence reflex], which trains them to automatically adjust their optical focus (accommodation) based on the perceived distance to the objects (vergence) that they are looking at. This helps make focusing quick and accurate.
The problem occurs because our eyes have an [https://en.wikipedia.org/wiki/Accommodation_reflex accommodation-vergence reflex], which trains them to automatically adjust their optical focus (accommodation) based on the perceived distance to the objects (vergence) that they are looking at. This helps make focusing quick and accurate.


When a virtual object appears to be mere inches in front of the user’s face, but the image of that object is, optically, several meters away (as it is in common HMD design), the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.
When a virtual object appears to be mere inches in front of the user’s face, but the image of that object is, optically, several meters away (as it is in common HMD design), the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.
Line 17: Line 19:


The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.
The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.
{{Creative Commons text attribution notice|cc=zeroXVRWiki|url=https://www.xvrwiki.org/wiki/Vergence-accommodation_conflict}}


==References==
==References==
Line 23: Line 27:


* Gregory Kramida and Amitabh Varshney, [https://www.cs.umd.edu/sites/default/files/scholarly_papers/Kramidarev.pdf Resolving the Vergence-Accommodation Conflict in Head Mounted Displays]
* Gregory Kramida and Amitabh Varshney, [https://www.cs.umd.edu/sites/default/files/scholarly_papers/Kramidarev.pdf Resolving the Vergence-Accommodation Conflict in Head Mounted Displays]
* Oliver Kreylos, [http://doc-ok.org/?p=1360 Head-mounted Displays and Lenses]


[[Category:Terms]]
[[Category:Terms]]