I Have A 40 Year Old Black Daughter Who Was

I have a 40 year old black daughter who was planning had planned her wedding in the process of the stress from planning it she had a headache for about a month or two everyday she would go home from work and go to bed try to relieve this headache long story short after the wedding she finally went to the emergency room and they did an mri and she was blind in her right eye no vision and today her vision has still not returned she going to a optomolgist but im confused as to what happen did a migraine cause this