Hi there wondering if you can help, about 4 years ago i suddenly developed anisocoria in left eye after a recent fall where i really jolted my spine and neck it was eventually diagnosed as a horner's syndrome after cocaine eye drop test and i was sent for firstly a cta scan of carotid and vertebral arteries which was fine although by time i was sent for scan symptoms seemmed to be improving.I was also sent for further brain mri 2 months later as iwas continuing to have dizzy spells and visual jumps as well but it came back completely normal.Soon after this a really weird thing happened the pupil that had been the small(horner's) pupil suddenly became the lager pupil and the normal pupil became the smaller one especially in dark and it stayed this way until recently where it has reversed again and now it is back the way it was 3 years ago.I am baffled at this alternating anisocoria and possibly alternating horners and so are my doctors as i also had complete upper ct body scan which was completely clear apart for swollen lymph nodes and an eventually axillary biopsy which proved negative,i am going back to gp again but can anybody shed any light on this,thanks paolo