Hi-- my dad has had MS for the past 35 years. He was diagnosed 6 months before I was born.
What the doc told you is not true, although he may just not know all the different ways the disease can display itself-- believe me, I heard the stories of when my Dad was first diagnosed. He first went blind in one eye, the next day it was the other, but the first was fine. He's had eye tests at various times over the years, and the tests will be fine, or he'll be prescribed glasses, and within a couple weeks his vision will change again.
I recommend finding a specialist as soon as you can so you get the info you need-- a general pract just can't know EVERYTHING on every disease, and try the MS society for more info.
All the best,