I had blurred vision with candida and mercury toxicity. It's a pretty common symptom. But it appeared to come on with the addition of braces on my teeth and remained from then on. It went away later when I removed sugar/wheat/gluten/yeast from my diet. Even my asthma lessened substantially.

So even though I still had mercury poisoning, just the dietry changes alone made a big difference to me. And in many other areas also.