I wonder we often here that one of the pivotal events of Hitlers life was then he was subject to a poison gas attack during WW1, and where his lost his eyesight temperaly.
But what if he had went permanently blind?? Which kind of Hitler would we have had? Could he still have become the Hitler in OTL?
Apparently the blindness was not physical, it was psychological, and he actually had another bout of it later on.
But anyway, I suppose blindness makes it harder for him, but he still could have turned out to be the same Hitler. On one hand it makes him a little less charismatic, sorry don't mean to be offensive but it would have done, on the other hand the sight of this man consumed by power and 'vision' having sacrificed so much for his country may have increased his support amongst the German voter.
Not being able to read maps may have caused him to interfere less in military matters, which may have been a bonus!