Was just reading in toxicology and applied pharmacology that
Exposure to methyl mercury from birth to adulthood impairs high-frequency hearing in monkeys...

http://www.sciencedirect.com/scienc...amp;md5=6de66fec7cda4ac942dcf0299a754612

Hearing deficits being a frequent consequence with methyl mercury exposure in humans and it talked about previous results in this group of monkeys
in which deficits in spatial and temporal visual function were observed as well.

Interesting observations..
I know the pink disease survivors reported haveing auditory problems as well..
Mercury effects the brain and the hearing it's a known fact it can..
Go together..
And then the visual too..