Dear Welcome to HCM We understand your concerns I went through your details. I suggest you not to worry much. Post Traumatic Stress Disorder has lot of other symptoms. Diagnosis is confirmed when majority of symptoms are matching. If you have only this vision problem, then it can be just a case of obsessive thinking. Your experience do not confirm to be a traumatic one, more aptly shocking one. In such cases, the shock should go away within about some months. In your case, you are just 14, saw your grandmother die. As you are young, you did have negative aspect to this natural phenomena. Don t worry. Just ignore and reassure that you loved her and grandma loved you as well. because she loved you so much, you were lucky enough to be at her side when she died. Ignore the vision and love your grandmother, don t fear. If you require more of my help in this aspect, Please post a direct question to me in this website. Make sure that you include every minute details possible. I shall prescribe some psychotherapy techniques which should help you cure your condition further. Hope this answers your query. Available for further clarifications. Good luck.