Changes

Judder is a mixture of smearing and strobing. Judder can significantly reduce visual quality of a [[VR]] display. The smear aspect of the Judder is caused by low [[refresh rate]] or high [[persistence]] of the display. As smear occurs when each pixel moves across the retina while it is lit, smear occurs. <ref>http://blogs.valvesoftware.com/abrash/down-the-vr-rabbit-hole-fixing-judder/</ref>

Judder can be reduced by increasing the [[refresh rate]] of the display. When refresh rate is high enough, judder will not longer be visible to the human eyes, effectively eliminating the phenomenon. To truly eliminate smear, refresh rate of 1000 Hz is needed. Currently this is almost impossible to do due to technical limitations. Another, more practical, method is to use [[low persistence]] display. In a low persistence display, each pixel is lit for a very short amount of time, less than 2 ms. Lit pixel will no longer move across the retina, removing smear.