How to supplement eyesight without eyeglasses and contact lenses in case of emergency

ByJason Wong

In the event of an emergency such as glasses or contact lenses can not be taken out in the event of a disaster or glasses are broken when there is no spare, there is a possibility that anyone can fall into the emergency. We publish many physical-related movies on YouTubeminutephysicsA movie that shows how to supplement eyesight as a first aid measure at such a time is released on the channel.

How to See Without Glasses - YouTube


Sight is a very important feeling for humans. Although I can "imagine" the world with words, stories, sounds etc ... ...



By eye, you can understand with a single shot.


Because it is such a precious feeling, people pay a lot of money to the eyes, such as eyeglasses, contact lenses and LASIK surgery, to prevent vision from disappearing.


For example, if a person wearing glasses loses important glasses ......


The visibility is interrupted, making everyday life and behavior difficult. Even in such a case, there is an easy way to see clearly.


It is "just making a little ring with your fingers and peeping at one eye". The world peering through the hole should be clearly visible to some extent without glasses.


In order to know why you can see clearly just by peering into the hole, it is important to first know "how the eyes are visible".


I will think about "I can see flowers on a sunny day." Light from the sun as a light source strikes the flower, the light hitting the flower bounces back and jumps into the retina of the eye.


The brain interprets the image that jumped in and recognizes "flowers".


If the lens did not exist in the structure of the eye, the light would radially strike the retina of the eye which is responsible for reading the image ......


Because the retina can not read a concrete image, the brain can not interpret it. The same thing happens even if the lens is removed from the camera.


The lens has a function to converge the diffused light to one place and displays a clear image on the retina.


However, the lens has a fixed "focal length" and can only focus on light coming from a specific distance.


Even if it is a little, it gets blurred if it is too close or far.



Fortunately, the lenses of the human eye are connected to the muscles, so you can adjust the focal length with the muscles.



On the other hand, small holes like pinholes are different from lenses and focus on any distance.


This is because the opening is so small that only light from a specific direction does not reach it.


In other words, rather than converging multiple lights to create an image, by blocking out some of the lights, it creates a clear image. Naturally, the amount of light is small, so the image gets dark.


Because glasses and telescopes adopt lenses rather than pinholes because of the difficulty in seeing the image as dark, if there are no lenses, there are also hands that make simple pinholes with fingers and substitute functions It is that.