The eye has been called “the window to the soul” by people who have no idea how it works.
There were once a variety of theories on how we see:
Extramission: The theory that eyes emit a light, like the fire of the sun, onto objects they see, and then the image object is reflected back onto the water of eye.
Intromission: The theory that everything projects a smaller version of itself, with a smaller number of atoms, in all directions. The eye catches this smaller image.
Intermission: The break in a long film, when your eyes get watery from looking at the screen in the dark for so long.
But now what causes vision more clearly, even if we don’t see objects in front of us as clearly as we used to.
You might thing the third “intermission” definition is a joke, but think again. Spending a lot of time indoors, whether it be on the computer or watching a movie, may have an adverse effect on eyesight. And, more people suffer from poor eyesight than before.
I remember when fewer than a quarter of people needed glasses. My father needed them when he was about my age, but he only just started to need them and didn’t want to admit it.
I recently heard that more than half the population uses some kind of glasses or contact lenses to see well. Now, if ageing were the only cause, then we wouldn’t expect to see the rise among young children. But, according to the Australian consumer magazine “Choice”, myopia is on the rise among young children.
The reason they give is that bright sunlight is needed to develop the eyes. As children spend more time indoors, their eyes don’t develop properly. However, the video they provide is a bit simplistic.
For instance, the boys playing basketball inside are probably working hard to develop their eyes by constantly changing focus, which the boy playing video games outside might be getting some sunlight reflected, but isn’t really adapting his eyes with focus. Perhaps sunlight has an influence on myopia, but there are other kinds of health and eyesight problems to think about.
There are many other causes of eyesight problems. One is diet, and from my observation people don’t eat as many vegetables as they used to. Vitamin A deficiency was once one of the major causes of blindness. But, vitamin A is not the only vitamin to affect vision. According to an article in the BBC, you might be able to improve your vision by improving your diet, even after your eyes have developed.
Another recently suggested is that marijuana causes eyesight impairment. In the Independent, a newspaper that used to campaign for the legalisation of marijuana, it has been suggested that regular marijuana use could lead to eyesight impairment. (warning, excessive advertisement makes that sight SLOW.)
Also, as more people suffer from diabetes, diabetes related illnesses are also on the rise. The WHO list diabetic retinopathy as one of the major causes of blindness among working age adults. According to NHS choices, high levels of sugar in the blood damage the retina in the back of the eye.