Hi, I'd like to weigh in here. First welcome to the forum and to our little Light Side of the Moon. You bring up a couple "age old" problems here.
First, the combination of vertigo, visual problems, and headaches is not necessarily a strong picture of MS. It could just as easily be a complex type of migraine. But, we answer questions here in the context of MS. And yes, all of those symptoms can certainly and commonly be seen in MS.
The first is whether people in their 50s normally have small hyperintensities on their brain MRIs. The answer is yes, commonly. However, such lesions are silent and do not cause symptoms. But, you have symptoms. Since you are of my generation you'll likely remember the movie. It is a true Catch-22.
What the good neurologist will ask when they view an MRI with such T2 lesions is, "Why was this MRI requested?" The answer is, "Because the person has neurological symptoms and I wanted to see if there were any lesions." So, there ARE lesions and the immediate response is to dismiss those lesions as normal. Huh?
Could the lesions on your MRI be just normally acquired ones due to your age? Yes, of course, but we have to also remember that not all people of your age have such lesions and such age-related lesions do not cause symptoms. Then we have to consider that the lesions "may" be related to the neurological symptoms. The smart, good neurologist will not dismiss them, but consider them suspicious and be driven to investigate more. Those lesions must be kept in mind.
I liken this to the store owner who comes in one morning to find his store trashed and valuable merchandise gone. He calls the police who send out investigators. They verify what the owner claims. So the detective says, "Go see if there is any evidence of forced entry." The police find that one of the windows is newly damaged and gouged, and that it can be jiggled open even when locked. There are new scuff marks on the window sill. So the detective says, "Oh, that. A lot of these old stores have problems with their windows." He turns to the owner and says, "There is no evidence that you have been robbed." And he leaves. Huh?
There are a couple things you can find out about your MRI as suggested by the others. First what the stregnth of the machine is. It will be reported as a number followed by a T. The T stands for Tesla, the unit of the magnet strength. The second is whether the MRI was done using the needed Protocol for MS.
Now, you have had a very good work up to date for the vertigo. The testing you had did not show that there is a cause in the inner ear for your vertigo. This implies that the cause is central within the 8th cranial nerve or in the brainstem, which would be consistent with MS. It doesn't prove a central cause, but suggests it.
Vestibular Rehab can be very helpful no matter what the cause of the vertigo.
Since you have definite visual symptoms I would wonder why they haven't done a formal visual fields test or a VEP (Visual Evoked Response). Both of those might yield some more information about your problem. When the ophthalmologist looks at your optic nerve one of the things he would have been looking for is signs of optic neuritis. The optic disc would be pale and thinned. But, optic neuritis does not show on the physical exam in more than 50% of cases. That is why the other tests would/could be helpful.
The neurologist seems to be under the very odd impression that each attack of MS must be different from the ones before it. This is just not true. Any series of given attacks may appear exactly like others, may have some similarities, or may be completely different. So, he seems undereducated on that point also.
I hope he didn't make any remark that you are too old. Though it is less usual, MS can and has been diagnosed into the 80's and seen to have it's first symptoms well into the 70's. There is no reason to beleive that there is some magical upper limit. My first symptoms were at 52 and my diagnosis at 54.
As for whether this is one attack (in the context of MS) or a series of attacks here is one set of definitions. If you haven't had a month where the symptoms were either improved or stable, then this is all one attack (if this is MS).
http://www.medhelp.org/health_pages/Multiple%20Sclerosis/Relapses--Pseudo-Relapses-and-Remissions/show/372?cid=36
So, I agree that a second opinion is definitely in order. Along with that the other tests I mentioned might also be helpful.
Hope you stick around as you go through this. We'll provide all the support and info we can.
Quix