Lentes especiales y auxiliares para mejorar la vista logran hacer el efecto ejercitar los músculos que se endurecen y crean la miopía, el astigmatismo.
incluye cd interactivo para hacer ejercicios.
you suffer from myopia (near-sightedness), hyperopia (long-sightedness), presbyopia, astigmatism, computer vision syndrome or cataracts?
How pinhole glasses work
To fully appreciate how pinhole glasses work it is necessary to understand how the eye processes light rays to form an image.
How the eye works:
Light enters through the cornea - a convex transparent membrane that covers the eyeball. Its curved shape allows light entering from different angles to be concentrated into a beam of light that enters the pupil.
The pupil regulates the amount of light that enters the eye, and passes the beam of light into the lens The lens focuses the beam of light through the vitreous humour and onto the retina near the back of the eyeball.
The ciliary muscle controls the lens so to give it the right shape to enable exact focusing of the image on the retina.
On reaching the retina, that is the part of the eye that is actually sensitive to light, it transmits the information to the optic nerve, which in turn sends the image to the brain.
Perfect vision in the unaided eye requires the eye lens to focus light rays from diverse angles into a single pinpoint directly on the retina at the back of the eye.
For sufferers of refractive eye disorders, where the eye lens is too weak or the cornea or eyeball is misshapen, divergent light rays become focused in front of or behind the retina, casting an unfocused image onto the retina itself. This unfocused area of light is known as the 'blur circle'.
Pinhole glasses work by reducing the diversity of angles from which light rays can enter the eyes, allowing only direct light rays within a narrow angular path to strike the cornea. The lenses of pinhole glasses are perforated with an array of equally spaced minute holes of approx 1mm - 1.5mm in diameter. In contrast the average diameter of the pupil in normal daylight conditions is about 4mm. Each pinhole allows only direct rays through, and it is the amalgamation of these direct rays that make up a concentrated beam of light that enters the pupil. When this restricted light beam passes through the pupil and into the eye lens, the effects of any refractive eye disorders
are reduced as the 'blur circle' on the retina is proportionally smaller. The resulting visual image is one of increased clarity, definition and brightness.
Pinhole glasses are based on the principle of natural reflexes as the same effect is achieved when you squint to try and see more clearly. Your eyelids close around the top and bottom of your eyes, filtering out light rays eaching
your pupil from these angles. Only light from your central area of vision and to the left and right sides can now enter your eye. The image you see is often sharper with a greater depth of resolution, and is generally brighter as there is a narrower range of light levels to contrast against each other. Wearing pinhole glasses is of course much less stressful on the eye than squinting, and is far more efficient at blocking extraneous light rays to produce a sharper and brighter image on your eye.
Instant vision improvement
For people who have been diagnosed with myopia, hyperopia, presbyopia, astigmatism or cataracts, pinhole glasses offer instant relief through better vision. You'll really notice the difference when focusing in the middle to long
distance, such as when watching TV or reading from a classroom blackboard. Users of pinhole glasses report almost perfect vision and have little difficulty reading words or seeing definition in a TV image WITHOUT HEIR RESCRIPTION SPECTACLES.
Pinhole glasses do have some limitations to their uses. As the amount of light entering the eye is reduced it is strongly recommended that they are used in good lighting conditions. For instance, when reading a book make sure you have a good reading lamp close by. It should also be noted that pinhole glasses restrict peripheral vision, so they should not be used for tasks that require you to be in motion, such as driving.
It is also recommended that they not be used as a substitute for sunglasses, as there is no protection against the sun's harmful UV rays. Just as with all other glasses - NEVER USE THEM TO STARE DIRECTLY AT THE SUN, as this will cause blindness by painlessly burning and destroying the light sensitive cells on your eye's retina.
Young people who are very far-sighted and need to refine their visual acuity unaided, should certainly not consider pinhole glasses, or for that matter, any other visual aid to assist their eyesight. It is important for sufferers of
this condition to naturally overcome their far-sightedness by giving them every opportunity to build strength into their ciliary eye muscles. This will enable them to reduce their far-sightedness down to more manageable levels.
Equally, if any person is chronically myopic and is diagnosed with more than 6 diopters of near-sightedness, then pinhole glasses may not improve their vision significantly due to excessive problems with diffraction.
The Science of Pinhole Glasses
Pinhole technology is not a new discovery - far from it. As far back as the 5th Century BC, the ancient Chinese people discovered that light passing through a tiny pinhole makes an image on the background it falls upon.
Aristotle (384-322 BC), the great Greek philosopher, expanded on this, laying down the principle of pinhole imagery.
The first real application of pinholes came over 1,000 years later when Alhazen (Ibn Al-Haytham), used the principle to invent the pinhole camera - a light tight box through which a pinhole on the front surface of the box allows direct light rays to enter and form an image on the back of the box. This idea of capturing an image drove inventors and scholars in Renaissance Europe to explore the science of pinholes further, discovering that light moved in straight lines, unless refracted by a lens or some media that acted like a lens. This led to the invention of the Camera Obscura as a way of capturing a large image through a small lens.
Pinholes have been used to aid vision for hundreds of years. There is evidence that Eskimo communities have used fabrics and wood with narrow slits in as a primitive form of pinhole glasses, in order to protect their eyes from the glare of the sun off the snow and ice for many centuries. In the mid 20th Century, pinhole glasses for public use were pioneered. Although the first prototypes of pinhole glasses were unattractive, heavy and cumbersome to use, technological advances in materials, lasers and production methods have meant that the pinhole glasses of today are high-tech in comparison.
The medical profession too have adopted the science of pinholes as a way to measure visual acuity and to detect refractive vision disorders in their patients. Ophthalmologists often use a pinhole occluder to gauge visual acuity
on a 20/20 or 20/50 scale, and also to determine the extent of a patient's refractive error (measured in diopters).
This device is essentially a pinhole which is held very close to the patient's eye, and works on the principle that anything seen through a tiny hole will always be seen in focus. If the patient can see a target image through the pinhole more clearly than without the pinhole, then traditionally ophthalmologists prescribe eye glasses (logically, the ophthalmologist should prescribe pinhole glasses as he/she would have just proved that pinholes do improve vision!)
Honeycombing & Double Images
The science behind pinhole glasses is therefore proven by nature and approved by the medical profession. So why aren't pinhole glasses more popular? The truth is they are rising in popularity as more is understood about them.
One great myth that needs to be exploded is that pinhole glasses do not work because of the honeycombing effect.
This is when your eyes focus more on the opaque occluding plastic rather than the light rays passing through the pinholes, allowing you to 'see' the pinholes rather than the information transmitted through the pinholes.
Naturally, as with any new pair of glasses, your new pinhole glasses will take a little getting used to. Many people claim to be conscious of their eyeglass lenses and frames when they first wear them, but after a little time their brain gets used to the information it is receiving, so they notice the frames less. The same is true of the honeycomb effect. Providing you have a low refractive error then once you let your brain adapt to the improved visual information being received through the pinholes, then the honeycombing effect disappears! Honeycombing does become more of a nuisance at a higher refractive error index, and those with a refractive error of 6 diopters or more may find pinhole glasses impractical because of a persistent honeycombing effect.
The occurrence of double images is another factor that has historically deterred people from investing in a pair of pinhole glasses. However, with a greater understanding of how this happens we can see that as with the honeycombing effect, it only becomes a real problem for people who have a refractive eye disorder of 6 diopters or more.
Double images occur because light entering the minute aperture of the pinhole is slightly bent around the edges of the pinhole. This is known as diffraction, and happens to all light rays when they pass close to the edge of an object or opening. A well known example of diffraction is the swimming-pool phenomenon, when objects submerged in the water appear to be in a different location to where they actually are. This is because the water diffracts the light entering the pool, so the resulting reflection makes objects appear offset to where they really are.
With pinhole glasses, what you see is the offset image through more than one pinhole, giving rise to an apparent double image. For those with a low refractive index, this visual phenomenon is hardly noticeable, however, as the refractive error increases, so the double image becomes more pronounced.
1) Will pinhole glasses really improve my vision?
If you have a refractive eye disorder of less than 6 diopters, suffer from presbyopia (age-related eye deterioration), or computer vision syndrome, then the answer is undoubtedly YES. The minute pinhole apertures on the pinhole glass lenses, reduce the blur circle on your retina, so allow you to see more clearly. However, if you suffer from a refractive eye disorder of more than 6 diopters, then pinhole glasses may not work for you - see question 5)
2) What activities can I use pinhole glasses for?
You can use pinhole glasses for most activities where you are stationary, such as reading, writing, using a computer, watching TV, watching a theatre performance or reading notes of a school blackboard. Pinhole glasses are not recommended for activities where you are in motion, such as driving, as your periphery vision is severely curtailed.
3) Can I where pinhole glasses whilst driving?
No - you must never where pinhole glasses whilst driving as your periphery (side) vision is very limited, because pinhole glasses are designed to let only direct light rays through into your eyes.
4) Are pinhole glasses suitable for children?
Yes - pinhole glasses are ideal for children, especially those who are diagnosed with myopia. See our section on acquired myopia for further details.
5) My doctor says I have a refractive disorder of 6 diopters - will pinhole glasses work for me?
Not everyone with a refractive disorder of 6 diopters or more will find pinhole glasses practical, as problems with light diffraction and honeycomb vision become more prevalent to the point that they may outweigh the advantages. See our section on the science of pinhole glasses.
6) If my pinhole glasses arrive damaged what should I do?
We guarantee our pinhole glasses against defects. If your glasses arrive damaged then simply return them and we will send you a replacement pair ASAP.
7) What are the shipping costs?
Shipping costs are additional to the advertised product price at $5 usd. per pair.
8) How long will it take for my glasses to arrive?
We ship world-wide and dispatch goods within 48 hours of order receipt. Depending upon your location it should take between 2-5 working days.
9) What forms of payment do you accept?
We accept credit card & electronic check payments only through our webform at time of order.
10) Do the glasses come with a guarantee?
We guarantee the glasses against any defects. If you receive a pair of defect pinhole glasses please return the package to us and we will replace them free of charge with a brand new pair.
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Testimonials:
"I have worn your pinhole glasses for 4 months now mostly for reading and TV. I am so pleased with them as every time
I wear them my eyes feel more relaxed and I can see much more clearly than before. Thanks for everything!" Robert Mitchell - Washington D.C. USA
"What a relief - I am so glad I stumbled across your site! The TV picture has never seemed so clear - not even with my prescription lenses! I am now a bona-fide pinhole convert - thanks." Danni R. Etherman - W.Virginia USA
"I must say I was very skeptical about your pinhole glasses but I thought that I would try them out as I could note make out my tutors notes on the blackboard in our lecture hall. I am now very glad that I did try your glasses as I can now see the notes." Bethany Davis - Kingston