Originally posted 28 Aug 13.
Not everyone has Night Observation/Vision Devices available to them….yet. Many seem to believe that without night vision, one can’t do anything once the sun goes down and therefore, if it’s dark, whoever the opponent is with the most NVD owns the night. When discussing from the perspective of protecting the home and local neighborhood, the subject sometimes is so overwhelming that the thought of operating without NVD’s, street lights, or other forms of artificial light almost paralyzes otherwise adequately trained people.
DTG holds a different view: Low tech can, and in many cases will, overcome high tech, so long as the practicioner understands what he or she must master in order to achieve that goal.
The foundation that every other technique and tactic necessary to overcome high tech is called and gain the initiative in low light conditions is called, ‘Night Vision Techniques’.
It’s routinely ignored in various training seminars and rarely practiced, if what one can glean from otherwise well-trained people say is factual.
DTG’s purpose in this installment is to provide a means with which you, the reader, can begin to build the skills and confidence necessary to turn technological disadvantage around.
As with all other perishable skills, remember that consistent training is the key to operational effectiveness at night. According to H.John Poole’s research, during WWII, the Japanese fought many battles at night and when pitted man for man, outfought the American GI in the dark (what saved our guys was an abundance of flares and high volume suppression fire). The Japanese obviously practiced all their tactics in both daylight and darkness, with various modifications due to the changes one faces at night. But again, the first thing they had to achieve was how to see at night.
Let’s start with some Night Vision facts:
Human Eye Limitations
– Retinal Neuroreceptors: The human eye only has two – rods and cones. Rods are on the periphery and cones are in the center (fovea). Both are photoreceptors (neuroreceptors) that ‘fire’ when light hits the appropriate cell. With sufficent illumination, the cones process the image and gives us depth perception, fine detail and color, or ‘photopic vision’. Remember that only the very center of the fovea provides 20/20 vision — a bit off center and you’re out to 20/70!
– Rods take over in low light and provide peripheral vision, which are the cells that detect movement or threats. No detail, depth, or color is provided by them. This is why we have a hard time achieving detailed visual information in low light. This is called ‘scotopic vision’ and uses rods only.
– When the eye is able to use photopic and scotopic vision together in low light or various degress of darkness, it’s called ‘mesopic vision’ and is what your eyes measure on a moonlit or bright, starry night.
– As age progresses, the iris becomes less flexible and able to adapt to darkness (this truly sucks!). Caffiene, nicotine, and alcohol restrict blood flow to the eyes and further reduce the ability to detect movement or detail in low light or darkness.
Night Vision Development Requirements
– Time: It takes from 10 to 45 minutes to develop from 10 to 80% night vision capabilities. The last 20% takes hours or days, sometimes even a week of full darkness.
– Visual Purple Manufacture: Rhodopsin, or ‘visual purple’ has to be manufactured by the eye, and and is broken down very quickly by light….any light. It doesn’t take long for the visual purple to break down, either..half a second or slightly more.
How to Maximize Visual Purple Development
– Get the right amounts of Vitamin A in your diet. Lutein, 20mg per day, as a supplement will also help. Vitamin A or its precursor, Betacarotene is essential for visual purple.
– Green, leafy things eaten, followed by vegatables with an orange color (indicator of beta carotene content) including sweet peppers and carrots. Caution: Too much Vitamin A can be toxic, so make sure you get yours from vegatables if at all possible rather than supplements.
– Fitness – yes, here’s that dead horse again – Regular, vigorous exercise helps the eyes stay healthy. Don’t bitch….just do it.
– Quit smoking. Nicotine diminishes your ability to develop visual purple and subsequently see in the dark signficantly!
– Keep your blood sugar level as even as possible. Choose frequent small meals over large meals.
– Use dark neutral gray sunglasses that pass no more than 15% light in full sun in the daytime if the situation permits.
Next time….What kind of light to use in the dark and other related information…