EMDR is as Judy said, eye movement desensitization and reprocessing.  It is not just eye movement though, there are different ways to help distract the brain so the memory can be reprocessed.  My therapist uses these little hand held pods that are attached to a box by wires.  They vibrate back and forth between my hands.  So each hand has a pod and the pod vibrates for a second or two and then the other one does.  While you are feeling this sensation, you go into the memory with the help of the therapist, and start to reprocess.  Every 30 seconds or so the therapist takes you out to breathe and then go back into the memory.  Usually there are more memories or more information comes out during the session than you knew before you started.  That is why having a well trained therapist do the EMDR is crucial.  It is very helpful and very interesting how it works.  I love it!  I suffer from chronic severe depression, panic attacks and PTSD.