Do not know if dogs go blind if they eat sugar? The answer is simple, it is the same as when you wonder if dogs are blind if they eat chocolate.
Dogs are animals that can not have the same food as people, since dogs are more intolerant of certain types of food. And sugar is one of them.
Sugar itself can not blind a dog, which can be to make the dog develop diabetes. There are diabetic dogs, this means that certain dogs assimilate glucose worse than others, and accumulate it in large quantities in targeted places of your body.
One of the places where glucose can concentrate is in the eyes, so that the dog can develop cataracts and future blindness.