APOD: Sunspot Castle (2011 Nov 12)

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APOD: Sunspot Castle (2011 Nov 12)

Post by APOD Robot » Sat Nov 12, 2011 5:06 am

Image Sunspot Castle

Explanation: Each day can have a beautiful ending as the Sun sets below the western horizon. This week, the setting Sun added naked-eye sunspots to its finale, as enormous active regions rotated across the dimmed, reddened solar disc. Near the Sun's center in this closing telephoto view from November 7th are sunspots in Active Region 1339. Responsible for a powerful X-class flare on November 3rd, Active Region 1339 is larger than Jupiter. In the foreground, the ruined tower of a medieval castle stands in dramatic silhouette. Located in Igersheim, Germany and traditionally known as castle Neuhaus, it might be named Sunspot Castle for this well-composed scene.

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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by Case » Sat Nov 12, 2011 10:26 am

APOD Robot wrote:This week, the setting Sun added naked-eye sunspots to its finale
Wow. :o I didn't know naked-eye sunspots were possible. I'll be looking at sunsets more often.
I, for one, like Roman numerals.

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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by neufer » Sat Nov 12, 2011 12:54 pm

Image
Case wrote:
APOD Robot wrote:
This week, the setting Sun added naked-eye sunspots to its finale
Wow. :o I didn't know naked-eye sunspots were possible.
I'll be looking at sunsets more often.
http://en.wikipedia.org/wiki/Sunspot wrote: <<The earliest surviving record of sunspot observation dates from the 364 BC, based on comments by Chinese astronomer Gan De in a star catalogue. By 28 BC, Chinese astronomers were regularly recording sunspot observations in official imperial records. The first clear mention of a sunspot in Western literature, around 300 BC, was by Theophrastus, student of Plato and Aristotle and successor to the latter. A more recent sunspot observation was made on 17 March 807 AD by the Benedictine monk Adelmus, who observed a large sunspot that was visible for eight days; however, Adelmus incorrectly concluded he was observing a transit of Mercury. A large sunspot was also seen at the time of Charlemagne's death in 813 AD. Sunspot activity in 1129 was described by John of Worcester, and Averroes provided a description of sunspots later in the 12th century; however, these observations were also misinterpreted as planetary transits, until Galileo gave the correct explanation in 1612.

Studies of stratigraphic data have suggested that the solar cycles have been active for hundreds of millions of years, if not longer; measuring varves in precambrian sedimentary rock has revealed repeating peaks in layer thickness, at roughly eleven-year intervals. It is possible that the early atmosphere on Earth was more sensitive to changes in solar radiation than today, so that greater glacial melting (and thicker sediment deposits) occurred during years with greater sunspot activity,although alternate explanations have also been proposed. Analysis of tree rings has revealed a detailed picture of past solar cycles: Dendrochronologically-dated radiocarbon concentrations have allowed for a reconstruction of sunspot activity dating back 11,400 years, far beyond the four centuries of available reliable records from direct solar observation.>>
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by Beyond » Sat Nov 12, 2011 1:45 pm

I guess i just don't have a scientific mind. When i look at those sunspots all i think of is -- anti-zits.
Castle Neuhaus = neufer's house :?:
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by orin stepanek » Sat Nov 12, 2011 1:46 pm

APOD Robot wrote:
Explanation: Each day can have a beautiful ending as the Sun sets below the western horizon. This week, the setting Sun added naked-eye sunspots to its finale,
I cant look at the sun naked eye; not even at sunset! :roll: Too bright for me! Maybe with dark sunglasses! :?
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by orin stepanek » Sat Nov 12, 2011 1:50 pm

Oh I liked the picture; but I never seen the sky so dark at sunset! Especially with the Sun so high in the sky yet!
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by jasonbetksa » Sat Nov 12, 2011 1:51 pm

Are sun spots basically minature black holes. From what I understand, sun spots are areas on the sun that are so dense in gravity that light can't escape. Sounds something like a black hole. Is this true or not?

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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by luigi » Sat Nov 12, 2011 2:32 pm

orin stepanek wrote:Oh I liked the picture; but I never seen the sky so dark at sunset! Especially with the Sun so high in the sky yet!
We'd have to ask the photographer but I think it has to be a composite. I've been photographing sunrises for several months and the sky is never so dark around the sun that high in the horizon.
It's a great APOD to show that big monster sunspots can be seen with the naked eye and photographed without special equipment.

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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by neufer » Sat Nov 12, 2011 3:23 pm

jasonbetksa wrote:
Are sun spots basically minature black holes.
  • No.
jasonbetksa wrote:
From what I understand, sun spots are areas on the sun that are so dense in gravity that light can't escape. Sounds something like a black hole. Is this true or not?
Sun spots are areas on the sun that are so dense in magnetic field that heat can't escape by convective means.
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by neufer » Sat Nov 12, 2011 3:25 pm

orin stepanek wrote:
I cant look at the sun naked eye; not even at sunset! :roll:
Too bright for me! Maybe with dark sunglasses! :?
Make sure that they are sunglasses with UV protection.
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by Chris Peterson » Sat Nov 12, 2011 3:30 pm

jasonbetksa wrote:Are sun spots basically minature black holes. From what I understand, sun spots are areas on the sun that are so dense in gravity that light can't escape. Sounds something like a black hole. Is this true or not?
Sunspots are hot and blindingly bright- as high resolution images reveal. They are, however, a few thousand degrees cooler than the surrounding areas, so if you expose an image so that those areas are white, the sunspots will appear dark. It's all relative, and related to the way imaging and human vision work. Just as the surface of the Moon is black as coal, but looks white at night, sunspots can be white-hot and appear black in the "day" of the rest of the Sun.
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by luigi » Sat Nov 12, 2011 3:32 pm

neufer wrote:
orin stepanek wrote:
I cant look at the sun naked eye; not even at sunset! :roll:
Too bright for me! Maybe with dark sunglasses! :?
Make sure that they are sunglasses with UV protection.
Question for those that know: Are there sunglasses without UV protection? I thought plastic/glass was an UV blocker. I wonder if those sunglasses "with UV protection" have something special or just listing a property of plastic/glass.

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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by Chris Peterson » Sat Nov 12, 2011 3:38 pm

luigi wrote:We'd have to ask the photographer but I think it has to be a composite. I've been photographing sunrises for several months and the sky is never so dark around the sun that high in the horizon.
It's a great APOD to show that big monster sunspots can be seen with the naked eye and photographed without special equipment.
It certainly does not need to be a composite, and I doubt that it actually is.

Even at noon, if you expose an image so that the Sun is not saturated, the sky will look dark. There's no alternative given the dynamic range of cameras.

It is also worth keeping in mind that an image like this does not necessarily capture quite what the naked eye view would be. With the camera, there is the ability to optimize the dynamic range and choose the white and dark points in a way that our eyes cannot match. Properly constructed images are usually able to capture more than the eye can see... which is, of course, one of the reasons we image!
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by neufer » Sat Nov 12, 2011 3:40 pm

Click to play embedded YouTube video.
Beyond wrote:
I guess i just don't have a scientific mind.

When i look at those sunspots all i think of is -- anti-zits.

Castle Neuhaus = neufer's house :?:
STOP IT :!:
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by neufer » Sat Nov 12, 2011 3:46 pm

luigi wrote:
neufer wrote:
orin stepanek wrote:
I cant look at the sun naked eye; not even at sunset! :roll:
Too bright for me! Maybe with dark sunglasses! :?
Make sure that they are sunglasses with UV protection.
Question for those that know: Are there sunglasses without UV protection? I thought plastic/glass was an UV blocker. I wonder if those sunglasses "with UV protection" have something special or just listing a property of plastic/glass.
http://en.wikipedia.org/wiki/Ultraviolet wrote:
<<High intensities of UVB light are hazardous to the eyes, and exposure can cause welder's flash (photokeratitis or arc eye) and may lead to cataracts, pterygium, and pinguecula formation.

UV light is absorbed by molecules known as chromophores, which are present in the eye cells and tissues. Chromophores absorb light energy from the various wavelengths at different rates - a pattern known as absorption spectrum. If too much UV light is absorbed, eye structures such as the cornea, the lens and the retina can be damaged.

Protective eyewear is beneficial to those who are working with or those who might be exposed to ultraviolet radiation, particularly short wave UV. Given that light may reach the eye from the sides, full coverage eye protection is usually warranted if there is an increased risk of exposure, as in high altitude mountaineering. Mountaineers are exposed to higher than ordinary levels of UV radiation, both because there is less atmospheric filtering and because of reflection from snow and ice.

Ordinary, untreated eyeglasses give some protection. Most plastic lenses give more protection than glass lenses, because, as noted above, glass is transparent to UVA and the common acrylic plastic used for lenses is less so. Some plastic lens materials, such as polycarbonate, inherently block most UV. There are protective treatments available for eyeglass lenses that need it, which will give better protection.
>>
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by Chris Peterson » Sat Nov 12, 2011 4:01 pm

luigi wrote:Question for those that know: Are there sunglasses without UV protection? I thought plastic/glass was an UV blocker. I wonder if those sunglasses "with UV protection" have something special or just listing a property of plastic/glass.
Most popular eyeglass materials pass significant amounts of near-UV radiation (the wavelengths that are most problematic for the eyes). This includes glass, acrylics, and polycarbonates (CR39). All of these materials are normally treated specially to increase their near-UV absorption when used in eyeglasses. These days, you'd be hard pressed to find sunglasses without UV blocking.

FWIW, we are riding a peak in cataracts (and I made my fortune designing cataract removal instruments, so I'm not complaining <g>) caused by the popularity of sunglasses after the 1940s. For 50 years, people have worn sunglasses that didn't block UV, and this has resulted in the formation of many cataracts. Wearing such glasses is worse than wearing none at all, since the pupil responds to visible light. When you wear non-blocking sunglasses, the pupil opens wider and you end up getting more UV than you otherwise would. That's why it is so important to include UV blocking in glasses. (And these days, even ordinary eyeglasses and contacts have UV blockers.)
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by neufer » Sat Nov 12, 2011 4:20 pm

Chris Peterson wrote:
I made my fortune designing cataract removal instruments,
No kidding :!:

So astronomy was just a hobby then.
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by Chris Peterson » Sat Nov 12, 2011 4:51 pm

neufer wrote:
Chris Peterson wrote: I made my fortune designing cataract removal instruments,
No kidding :!:
So astronomy was just a hobby then.
No kidding. I initially majored in astronomy, than took my degree in physics. Started a company which designed and manufactured phacoemulsifiers for most of the major ophthalmic surgical companies. Maintained astronomy as a hobby over the years, and then got back into it semi-professionally in the late 1990s, after selling the phaco company and moving to our ranch in Colorado.

Cataracts have been very good to me <g>. I'm completely comfortable with the idea of vibrating needles thrust into eyeballs.
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by Beyond » Sat Nov 12, 2011 4:57 pm

Chris Peterson wrote:
neufer wrote:
Chris Peterson wrote: I made my fortune designing cataract removal instruments,
No kidding :!:
So astronomy was just a hobby then.
No kidding. I initially majored in astronomy, than took my degree in physics. Started a company which designed and manufactured phacoemulsifiers for most of the major ophthalmic surgical companies. Maintained astronomy as a hobby over the years, and then got back into it semi-professionally in the late 1990s, after selling the phaco company and moving to our ranch in Colorado.

Cataracts have been very good to me <g>. I'm completely comfortable with the idea of vibrating needles thrust into eyeballs.
I see.
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by Chris Peterson » Sat Nov 12, 2011 5:01 pm

Beyond wrote:I see.
Indeed. And if you're over 65 or 70, it might be because of my tech <g>.
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by luigi » Sat Nov 12, 2011 5:12 pm

Thank you for the answer about UV! Now I know.
About the image you are right about the exposure for the sun and the rest of the sky, if the sun is not overexposed the rest of the sky will be dark. I would like to ask the photographer anyway because the brighntess of the sky, foreground and the white balance look totally different compared to what I can get in a single shot. Specially the WB seems to be different between the sky and the sun. I always get red/orange skies near sunrise and sunset.

I have absolutely nothing against composites but if this is not one then it's something new to me and I would love to learn how to take a photo like this one in a single shot.

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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by orin stepanek » Sat Nov 12, 2011 5:45 pm

neufer wrote:
orin stepanek wrote:
I cant look at the sun naked eye; not even at sunset! :roll:
Too bright for me! Maybe with dark sunglasses! :?
Make sure that they are sunglasses with UV protection.
Thanks for the advice Art; but I won't look at the sun at all. :wink: I'll look at the photos though. 8-) :D And today's was a great one. 8-)
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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by zloq » Sat Nov 12, 2011 6:54 pm

Chris Peterson wrote:FWIW, we are riding a peak in cataracts (and I made my fortune designing cataract removal instruments, so I'm not complaining <g>) caused by the popularity of sunglasses after the 1940s. For 50 years, people have worn sunglasses that didn't block UV, and this has resulted in the formation of many cataracts. Wearing such glasses is worse than wearing none at all, since the pupil responds to visible light. When you wear non-blocking sunglasses, the pupil opens wider and you end up getting more UV than you otherwise would. That's why it is so important to include UV blocking in glasses. (And these days, even ordinary eyeglasses and contacts have UV blockers.)
Do you happen to have a reference for this? I have certainly heard it numerous times - but I have never seen an actual study to prove a connection - saying that wearing early model sunglasses has caused an increase in cataracts in today's older population. It's not trivial at all since it involves an estimate of the dilation of the pupil coupled with the expected transmission loss due to the optical materials in use. If it's a situation of bright sun and glare, your pupil will be small anyway but the scene will appear darker thanks to the sunglasses - and any reduced transmission of harmful radiation will have benefit over no eyewear at all.

The argument against inferior sunglass use is self-consistent and often mentioned in discussions like these - but I'm asking if there is an actual published medical study that showed a connection.

As for how things are nowadays - most eyeglass material is very effective at blocking UVB radiation, with varying impact on UVA, even without a tint. There is growing concern for HEV light (in the visible blue-violet) as a cause of macular degeneration - so even perfect UVA blocking may not be an adequate safeguard against general eye damage.

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Re: APOD: Sunspot Castle (2011 Nov 12)

Post by Chris Peterson » Sat Nov 12, 2011 7:12 pm

zloq wrote:Do you happen to have a reference for this? I have certainly heard it numerous times - but I have never seen an actual study to prove a connection - saying that wearing early model sunglasses has caused an increase in cataracts in today's older population.
Not a handy one. But I've read several peer reviewed papers on the subject, with a rigorous analysis of the optical characteristics of lens materials and pupil response, and supported by statistical information regarding cataract rates and age of onset. Those papers would have been published in the early 1990s.
As for how things are nowadays - most eyeglass material is very effective at blocking UVB radiation, with varying impact on UVA, even without a tint.
Yes... but in reference to the earlier question, this involves additives to the plastic (or glass coatings) that are designed to make it this way. While most plastics do have a sharp cutoffs in transmission at short wavelengths, they can still pass unacceptable amounts of near-UV in their unmodified formulations.
There is growing concern for HEV light (in the visible blue-violet) as a cause of macular degeneration - so even perfect UVA blocking may not be an adequate safeguard against general eye damage.
Yes, there is good evidence of this- especially in people with certain genetic or pathological disposition to these diseases. The phenomenon of phototoxicity has been well described for several decades- that is, where bright light, but well inside the intensity range normally considered safe, causes severe and sometimes permanent retinal damage. It is a concern for ophthalmic surgeons (including those removing cataracts), as such surgery normally involves shining rather bright light into the eye.
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Post by neufer » Sat Nov 12, 2011 7:50 pm

Chris Peterson wrote:
neufer wrote:
Chris Peterson wrote:
I made my fortune designing cataract removal instruments,
No kidding :!: So astronomy was just a hobby then.
No kidding. I initially majored in astronomy, than took my degree in physics. Started a company which designed and manufactured phacoemulsifiers for most of the major ophthalmic surgical companies. Maintained astronomy as a hobby over the years, and then got back into it semi-professionally in the late 1990s, after selling the phaco company and moving to our ranch in Colorado.

Cataracts have been very good to me <g>. I'm completely comfortable with the idea of vibrating needles thrust into eyeballs.
http://www2.nau.edu/~tas3/handel.html wrote: <<Georg Friedrich Handel (1685-1759) was born in Halle (50 miles from Eisenach, Bach's birthplace) in the same year as Bach. Handel sojourned in Italy in 1706 where he met Corelli, and both Scarlattis. His return to Hanover, four years later, was to assume the post of Kapellmeister to the Elector (soon to become king George I of England). In 1712 Handel moved to London where, upon the accession of the house of Hanover, two years later, he gained immediate access to the royal circle of England. In 1717 Handel succeeded Pepusch as chapel master to the Duke of Chandos. Handel's London years were occupied primarily with the writing of Italian operas. After suffering a stroke and the failure of his operas, Handel wrote oratorios, including "Messiah" (1741). Handel's eyesight failed him in later years and he eventually became completely blind.

In 1719 Handel returned to his birthplace, Halle, for eight days. At that time Bach lived in Cöthen, twenty miles away. Bach's admiration for Handel is evident from his having copied, with the help of his wife, a passion and other works by Handel. Knowing that Bach wanted to meet Handel, Prince Leopold lent Johann Sebastian a horse. For reasons that remain a mystery, the meeting never took place. Spitta indicates that Bach's admiration for Handel was not reciprocated. In one of the curious ironies of music history, both men would be afflicted with cataracts in their old age and undergo surgery at the hand of the same oculist, John Taylor. By today's standards, this surgery was extremely crude, and any improvement to the visual impairment would have been minimal at best. It involved physically shoving the cataract-covered lens back into the eyeball in an attempt to allow a little more light to enter. (Bach would die from septicemia induced as a consequence of contaminated instruments). As this surgery was done without anesthesia, the courage and physical constitution of both men must have been amazing! Bach owned a copy of Handel's Brockes Passion, "Armida abbandonata" and the Concerto grosso in F minor. Thematic similarities in some of Bach's cantatas suggest that he may have been familiar with Handel's opera, "Almira".>>
http://en.wikipedia.org/wiki/Cataract wrote:
<<Cataract derives from the Latin cataracta meaning "waterfall" and that from the Greek καταράκτης (kataraktēs) or καταρράκτης (katarrhaktēs), "down-rushing", from καταράσσω (katarassō) meaning "to dash down"(from kata-, "down"; arassein, "to strike, dash"). As rapidly running water turns white, the term may later have been used metaphorically to describe the similar appearance of mature ocular opacities. In Latin, cataracta had the alternate meaning "portcullis" and it is possible that the name passed through French to form the English meaning "eye disease" (early 15c.), on the notion of "obstruction". Early Persian physicians called the term nazul-i-ah, or "descent of the water"—vulgarised into waterfall disease or cataract—believing such blindness to be caused by an outpouring of corrupt humour into the eye.

The earliest records are from the Bible, as well as early Hindu records. Early cataract surgery was developed by the Indian surgeon, Sushruta (6th century BCE). The Indian tradition of cataract surgery was performed with a special tool called the jabamukhi salaka, a curved needle used to loosen the lens and push the cataract out of the field of vision. The eye would later be soaked with warm butter and then bandaged. Though this method was successful, Sushruta cautioned that it should only be used when necessary. Greek physicians and philosophers traveled to India where these surgeries were performed by physicians. The removal of cataract by surgery was also introduced into China from India. The first references to cataract and its treatment in Ancient Rome are found in 29 CE in De Medicinae, the work of the Latin encyclopedist Aulus Cornelius Celsus. The Romans were pioneers in the health arena—particularly in the area of eye care. The Muslim ophthalmologist Ammar ibn Ali, in his Choice of Eye Diseases, written circa 1000 CE, wrote of his invention of the hypodermic needle and how he discovered the technique of cataract extraction while experimenting with it on a patient.

Age-related cataract is responsible for 48% of world blindness, which represents about 18 million people, according to the World Health Organization (WHO :owl: ). In many countries, surgical services are inadequate, and cataracts remain the leading cause of blindness. As populations age, the number of people with cataracts is growing. Cataracts are also an important cause of low vision in both developed and developing countries. Even where surgical services are available, low vision associated with cataracts may still be prevalent, as a result of long waits for operations and barriers to surgical uptake, such as cost, lack of information and transportation problems.

Cataracts develop for a variety of reasons, including long-term exposure to ultraviolet light, exposure to radiation, secondary effects of diseases such as diabetes, hypertension and advanced age, or trauma (possibly much earlier); they are usually a result of denaturation of lens protein. Genetic factors are often a cause of congenital cataracts. Cataracts may also be produced by eye injury or physical trauma. A study among Icelandair pilots showed commercial airline pilots are three times more likely to develop cataracts than people with nonflying jobs. This is thought to be caused by excessive exposure to radiation coming from outer space. Supporting this theory is the report that 33 of the 36 Apollo astronauts involved in the nine Apollo missions to leave Earth orbit have developed early stage cataracts that have been shown to be caused by radiation exposure to cosmic rays during their trip. At least 39 former astronauts have developed cataracts; 36 of those were involved in high-radiation missions such as the Apollo missions. Cataracts are also unusually common in persons exposed to infrared radiation, such as glassblowers, who suffer from "exfoliation syndrome". Exposure to microwave radiation can cause cataracts. Atopic or allergic conditions are also known to quicken the progression of cataracts, especially in children. Cataracts can also be caused by iodine deficiency.>>
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