Hi, I'm new here, wife is getting migraines in eye

Hello,
My wife is 38 and for the past 3 or 4 years has been getting migraines around the time of her period. She will usually get on average 4-6 of them per month, clustered around the week of her period. The migraines are usually always located behind and around her right eye. She can usually feel them coming on and will take an immitrex, which usually helps. Her neurologist wants to do a MRI to rule out anything else (he said tumors are rare, is he right? and she has no other symptoms). But he did seem a little puzzled that her migraines are always in the same eye. I thought that is the usual pattern with migraines, they usually affect the same location. Is this correct?