Sandy Williams
The technology of pinholes is not new. Neither was it invented by man. Use of principle of pinholes by nature can be seen in the eyes of the mollusk Nautilus found in the Indian and Pacific oceans. It uses its pinhole eyes effectively to scavenge for food.
The science behind pinholes has been known to man since 5th Century BC. Since then he has tried variously to use this knowledge to his benefit. The Ancient Chinese seem to be the first to observe the pinhole effect. They observed that rays from an object would cast an inverted image when passed through a pinhole. Using it, they cast pinhole images of a model 'Pagoda' (a type of tower in Oriental temples) on a screen inside the temple premises.
Later, in the 4th Century BC, Aristotle makes a mention in his book 'Problems', of the curious behavior of sunlight when viewed through a pinhole. It took 2000 years to find solutions for the questions concerning light raised by the philosopher in that book.
Arab mathematician and physicist, Ibn al-Haytham too experimented with the effect of pinholes on candle-light. His observations led to the discovery of linear behavior of light rays.
Ever since then, the principle of pinholes has been used for varied purposes like telling time(Cathedral of Florence, Paolo Toscanelli, 1475), by artists as an aid for drawing (Camera Obscura, Renaissance artists) and for making the Pinhole Camera.
Pinholes as an aid to vision
Eskimos seem to be the first in using the principle of pinholes for helping eyesight. They struggled from the glare of sunlight as it reflected from ice as they went about their daily life. Ingenuously, they used wooden spectacles with very narrow slits to overcome this problem.
Today, Ophthalmologists use instruments based on this principle in diagnosing vision related problems. They use these instruments typically on their patients to measure the sharpness of their vision.
They also use this principle in a piece of equipment called a Pinhole Occluder to check whether vision related problems in their patients are due to refractory errors or not. Patients with refractory errors are seen to have better vision when using this tool than when not using it.
Use of Pinhole Glasses
Even though nature attests the veracity of its effectiveness and modern medicine makes use of its principles, use of pinhole glasses is not as popular as it ought to be.
However, because of a wider spread of word about this tool and resolution of irrelevant problems associated with its use, more and more people are taking interest and availing of its benefits.
Most persistent amongst these problems is what is known as the “Honeycomb Effect”. It arises from a notion that viewing through pinhole glasses would be like viewing through a honeycomb; that you would not be able to see any images at all; that all you would get to see is a lot of plastic.
This has been seen to be untrue and is really a matter of adjustment. For instance, people new to wearing spectacles would testify to the fact that initially a large part of their field of vision is taken up by the frame of their glasses. But after some time, when the brain gets adjusted to the glasses, one no longer perceives the frame.
Similarly, when using pinhole glasses initially the glasses might be more prominent in your vision. But after your eyes get adjusted, you will enjoy nothing but clearer vision.
Diffraction
Another problem that deters people from buying pinhole glasses is reports by some users of occurrence of double images when using them. To understand this problem, it is necessary to know the science behind it.
It is a common phenomenon, and one that can easily be attested to, in daily life that light bends around the corner of objects. Closely observe a shadow formed from a single light source. You will observe a fringe on the edges of the image. This is an example of diffraction or the phenomenon of bending of light rays.
Diffraction happens when light rays pass through the edges of small holes like those in pinhole glasses. Since in these glasses light rays will be entering from multiple holes, you will see fringes bordering the image.
For people with low refractory errors i.e. with lens requirements of less than 6 diopters, this would be hardly noticeable and would pose no problems. But for higher ratings, the diffraction would be significant enough to prevent the user from seeing a clear image. This is the reason why pinhole glasses are not advised for people who have refractive errors greater than 6 diopters.
In fact, at such high ratings, the 'honeycomb effect' explained earlier too will prevent users from experiencing the benefits of wearing pinhole glasses.
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Sphere: Related Content
The technology of pinholes is not new. Neither was it invented by man. Use of principle of pinholes by nature can be seen in the eyes of the mollusk Nautilus found in the Indian and Pacific oceans. It uses its pinhole eyes effectively to scavenge for food.
The science behind pinholes has been known to man since 5th Century BC. Since then he has tried variously to use this knowledge to his benefit. The Ancient Chinese seem to be the first to observe the pinhole effect. They observed that rays from an object would cast an inverted image when passed through a pinhole. Using it, they cast pinhole images of a model 'Pagoda' (a type of tower in Oriental temples) on a screen inside the temple premises.
Later, in the 4th Century BC, Aristotle makes a mention in his book 'Problems', of the curious behavior of sunlight when viewed through a pinhole. It took 2000 years to find solutions for the questions concerning light raised by the philosopher in that book.
Arab mathematician and physicist, Ibn al-Haytham too experimented with the effect of pinholes on candle-light. His observations led to the discovery of linear behavior of light rays.
Ever since then, the principle of pinholes has been used for varied purposes like telling time(Cathedral of Florence, Paolo Toscanelli, 1475), by artists as an aid for drawing (Camera Obscura, Renaissance artists) and for making the Pinhole Camera.
Pinholes as an aid to vision
Eskimos seem to be the first in using the principle of pinholes for helping eyesight. They struggled from the glare of sunlight as it reflected from ice as they went about their daily life. Ingenuously, they used wooden spectacles with very narrow slits to overcome this problem.
Today, Ophthalmologists use instruments based on this principle in diagnosing vision related problems. They use these instruments typically on their patients to measure the sharpness of their vision.
They also use this principle in a piece of equipment called a Pinhole Occluder to check whether vision related problems in their patients are due to refractory errors or not. Patients with refractory errors are seen to have better vision when using this tool than when not using it.
Use of Pinhole Glasses
Even though nature attests the veracity of its effectiveness and modern medicine makes use of its principles, use of pinhole glasses is not as popular as it ought to be.
However, because of a wider spread of word about this tool and resolution of irrelevant problems associated with its use, more and more people are taking interest and availing of its benefits.
Most persistent amongst these problems is what is known as the “Honeycomb Effect”. It arises from a notion that viewing through pinhole glasses would be like viewing through a honeycomb; that you would not be able to see any images at all; that all you would get to see is a lot of plastic.
This has been seen to be untrue and is really a matter of adjustment. For instance, people new to wearing spectacles would testify to the fact that initially a large part of their field of vision is taken up by the frame of their glasses. But after some time, when the brain gets adjusted to the glasses, one no longer perceives the frame.
Similarly, when using pinhole glasses initially the glasses might be more prominent in your vision. But after your eyes get adjusted, you will enjoy nothing but clearer vision.
Diffraction
Another problem that deters people from buying pinhole glasses is reports by some users of occurrence of double images when using them. To understand this problem, it is necessary to know the science behind it.
It is a common phenomenon, and one that can easily be attested to, in daily life that light bends around the corner of objects. Closely observe a shadow formed from a single light source. You will observe a fringe on the edges of the image. This is an example of diffraction or the phenomenon of bending of light rays.
Diffraction happens when light rays pass through the edges of small holes like those in pinhole glasses. Since in these glasses light rays will be entering from multiple holes, you will see fringes bordering the image.
For people with low refractory errors i.e. with lens requirements of less than 6 diopters, this would be hardly noticeable and would pose no problems. But for higher ratings, the diffraction would be significant enough to prevent the user from seeing a clear image. This is the reason why pinhole glasses are not advised for people who have refractive errors greater than 6 diopters.
In fact, at such high ratings, the 'honeycomb effect' explained earlier too will prevent users from experiencing the benefits of wearing pinhole glasses.
READ MORE
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