Human Eye / Alterations

[Adam]

Hello there. I'm writing a little science-fiction story, just for fun at the moment. I need help with an idea please.

It seems to me that we see the portion of the EM spectrum we see because the size of the retinal cells happens to be the size of that particular wavelength. If the size of those cells was increased or reduced slightly, would that alone enable us to see further up and down the spectrum a little?

 

[Stryder]

The way I see it (no pun intended), if you were to just enlarge the protein receptors you could have some problems like celluar damage, or small you could suffer from the same consequences but from ones outside our range like X-rays.

You then have the point that although those receptors recieve information, the information has to go along the optics nerve which too would have to be adjusted to the new specifications and then unencoded at the Occipital lobe.

All these increases would have their drawbacks and bonuses, but it would mean that the whole shape and size of the brain would have to change to cater, which in turn means the skull would have to be different.

Hope that helps

 

[scilosopher]

Well as Stryder said the thing that determines the wavelengths is the absorption spectra of our three light receptors. That's also why we have three primary colors (and that's why three colors in a TV will trick us into seeing color).

I'm pretty sure the determinant of the absorption spectra is something other than size. Bees actually see UV (but still only have three pigments so they're missing some larger wavelength stuff we see) and some sea creatures (I believe sea snails are an example) have a larger family of receptors and therefore see in more color dimensions than we do (they might have more trouble coordinating there wardrobe). I believe the max known is 17 ...

I also don't think the encoding would be an issue, one could most likely modify the receptors in such a way that the downstream signalling is unaffected. Increasing the number of receptors we use would cause problems though as the downstream apparatus probably couldn't handle that many channels (though I believe each visual cell only expresses one of the receptors and colors are determines by how those cells map their axons into the brain). You could probably arrange for the swap between bees and humans and have a person who could see UV, but not red/yellow/or green. Presumably UV would look red, yellow or green though.

If you were thinking about shrunken or enlarged person seeing in a different spectral range, I don't think that jibes with the science.