Can double vision be caused by concussion?

Yes, did this happen: To you? You can have a concussion with or without loss of consciousness. Possible symptoms include: visual changes, headache/ pressure of head, inability to recall what happened, dizziness, decreased coordination, ringing in the ears, confusion, slurred speech, nausea or vomiting & extreme fatigue. If this happened to you please seek medical care.

Yes: One mechanism is brain swelling affecting e.g. The sixth cranial nerve making the affected eye lag.

Yes: Concussions are hard to diagnose because the symptoms vary from person to person. The only thing that is consistent is that imaging (mri/ct) is negative. See a doctor if your symptoms are worsening or not improving to make sure that nothing else is going on.