I understand the two points of vision creates depth perception but using energy to focus with two eyes puts strain on my brain. Could we live with just 1 effectively?
In: Biology
Sure. But there’s also a failsafe in having two; an eye injury resulting in blindness is not that uncommon, but much rarer in two eyes at once. So while there’s some advantage in having depth perception, the real advantage is in not being totally blinded and left defenceless if an injury wrecks your eye.
Depth perception is a survival advantage, very few species of preditors don’t have it. Even prey animals have two eyes so they can see more around them.
The key here is to understand that you are a grossly outdated design for a very different time. The fact is, if you could travel back in time 35,000 years, the people you would encounter would be basically genetically identical to you.
That means that you and I, as we stand today, are an evolutionary product ideal for surviving in the environment as it was 35 millennia ago. Having 2 eyes gives you a much wider field of vision, and the depth perception that you mentioned previously. Those traits offer HUGE advantages for hunting prey, as well as avoiding being preyed upon yourself.
To further this point one need only look around in nature. You’ll find plenty of things with no eyes, and plenty of things with more than 2 eyes, but a single eye is extremely rare if found at all. More eyes are better for survival.
The best experiment you can do to find out first hand why we have or at least how we benefit from having two eyes, is as follows.
1. Hold one eye close or cover it with a patch.
2. Go for a jog in a forest
You’ll get a quick lesson in the value of depth perception, peripheral vision and field of vision.
All are impaired by having only one eye.
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