Blind

A little while ago I posted about Tetrachromats. Last week I read an article about the vision of dragonflies who have over thirty opsins in their eyes. Imagine among other things being able to understand the polarisation of light as one of the thirty inputs to blend that makes up a colour in your mind's eye. I spent a sleepless night trying to imagine what that would mean to our perception of the world. For example prey above, on or below the surface of a sheet of water would appear as different tones. Perhaps range becomes a tone. The implications are truly mind boggling and I can only conclude that with such a range of colour inputs, a dragonfly does not simply see the world with its eyes, it feels it, like a textured landscape.Yesterday I heard that two relatives have had to sell their beloved house, a house which fills the memories of my childhood. The news was heartbreaking, partly because because they are both now completely blind. I suffered another sleepless night trying to imagine never being able to see again.

Tetrachromats

It has been discovered that some people, probably a tiny proportion of women, can see extra colours in the red-orange range. There are devices that are designed to drive kids away with high pitch sound that older people cannot hear. We have long known that some people can't assimilate words as well as others. Autism deprives you of the ability to read the emotions of others. Then, of course, there are the blind and the deaf. 

What other blindnesses are there that we don't yet know?