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Night vision – beating evolutionary limitations

Humans might like to consider themselves the top dogs in the evolutionary food chain but our ability to camouflage  and night vision are horrible. If you’ve ever woken up in the middle of the night thirsty and your trip to the kitchen felt like an obstacle course devised by a drill sergeant from hell, you know exactly what I mean.

Man versus beast

Mammals with great night vision have an extra layer of tissue immediately behind their retina, reflecting light back to the retina and allowing for an increase in the light available for photoreceptors, humans don’t. And if that wasn’t enough of a disadvantage, the rods of our eyes are much less sensitive to light than those of vertebrates with good night vision.

As with many other biological limitations, we’ve learned to compensate our shortcomings through technology, in this case by developing devices that allow our eyes to absorb more light and work much like the tapetum lucidum in animals.

Human 2.0

Our first attempt at developing a device that enhances our night vision capabilities consisted of a very crude infra-red device developed towards the end of WWII. The bulky, ineffective devices have since been replaced by night vision monoculars, binoculars and goggles that greatly amplify ambient light levels in order to turn what would otherwise be a black nothing into recognizable features, objects and environments.

The objective lense of a night time device acts much like the extra layer of tissue behind an animal’s retina, absorbing light that can’t be seen by the naked eye and focusing it on an image intensifier. At this point, a photocathode converts it into electrons, which are drawn into a phosphor screen, causing it to emit visible light.

EV_IMG2

Does night vision damage your eyes?

Like with most technological advancements the question “Is it a health hazard” is bound to come up sooner or later. As we’ve seen, night vision devices amplify ambient light, that is not visible to our own eyes and turns it into scenes we can understand. These devices allow you to adjust brightness according to your own level of comfort, ensuring that you don’t overtax your eyes while using them. Is there a risk of straining your eyes? Sure, but not more so than watching TV or using a computer for long periods of time.

Even if you use the device during the day, you risk ruining it instead if your eyes. It may get awfully uncomfortable, since you’d experience a sensory overload, sure but it won’t blind you.

To sum up, you don’t need to stumble in the dark anymore, night vision binoculars, monoculars and scopes are not only widely-available and affordable but pose no danger to your health and let’s face it, they provide an awesome experience that nature has deprived us of.

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