We are all sorry to hear that your daughter is getting these symptoms and you must be very worried about her.
Nobody on this forum can diagnose your daughter but we can offer some advice and support. Given that your daughter has had two episodes of bilateral Optic Neuritis and one episode with some physical disability, there is a CHANCE that she does have MS but I would wait to see what the doctors say. You say you are waiting for a diagnosis - does this mean that they are waiting for the results of tests that may have been performed? You don't actually say whether any testing has been performed, such as MRI's of the brain and spinal cord, a lumbar puncture, etc., or other tests, but I am sure that they will need to do these before making a diagnosis.
As Kathy said, there are people that get recurrent attacks of optic neuritis but it doesn't necessarily mean they have MS. Often they have some other kind of auto immune inflammatory disease such as RA or AS. Did your daughter have any pain with this?
For your information only, optic neuritis can be an early sign of MS, especially if tests also reveal abnormalities in the patient's spinal fluid. Most people with MS also experience abnormal sensory feelings such as numbness, prickling, or "pins and needles" sensations on and off.
Statistics say that 55% of MS patients will have an attack of optic neuritis at some time or other and it will be the first symptom of MS in approximately 15 percent. One positive thing is that for some reason, visual problems tend to clear up in the later stages of MS if that is what your daughter is diagnosed with.
Keep us informed and let us all know what is going on if you can.
The exact same thing happened to my husband over a three year period. Unfortunately he was diagnosed with MS approximately 2 months ago. But we were also informed that having the bouts of blindness does not necessarily mean that your daughter has MS. Please keep the site posted on your daughters progress, and remember there are some extremely helpful people in this forum