Dwayne is a veteran of the war in Iraq. He is undergoing treatment for post-traumatic stress disorder. While keeping his head still, he reimagines surviving a blast that killed the rest of his unit while following a series of lights with his eyes. Dwayne is undergoing .

Post traumatic stress disorder (PTSD)

Explanation:

PTSD is a disorder people may develop in response to one or more traumatic events such as deliberate acts of interpersonal violence, severe accidents, disasters or military action. The major characteristics of this disorder is re-experiencing symptoms, those who suffer from it involuntarily re-experience aspect of the traumatic event in a distressing way through flashbacks which makes the person feel as if the event is occuring again.

Dwayne is suffering of Post traumatic stress disorder.