
Solar viewer (also known as solar viewing glasses or solar eclipse glasses) are special
eyewear designed for direct viewing of the
Sun. Standard
sunglasses
Sunglasses or sun glasses (informally called shades or sunnies; more names below) are a form of protective eyewear designed primarily to prevent bright sunlight and high-energy visible light from damaging or discomforting the eyes. They can ...
are unable to filter out eye damaging radiation. Solar viewers are required for safe viewing of solar events such as
eclipses. The recommended
optical density of this eyewear is 5.
Safety
According to the
American Astronomical Society (AAS) products meeting the
ISO 12312-2 standard avoids risk damage, and issued a list of reputable vendors of eclipse glasses. The organization warned against products claiming ISO certification, or even citing the exact standard number, but not tested by an accredited laboratory, or those bearing incomplete certification information. Another problem was counterfeits of reputable vendors' products, some even claiming the company's name (such as with American Paper Optics which published information detailing the differences between its glasses and counterfeits).
Eyewear made prior to 2015, may have a 3-year use limit before they can no longer effectively filter out UV radiation. Starting in 2015, products made with ISO 12312-2 can be used indefinitely as long as they have not been damaged by scratch or tear.
Counterfeit eclipse glasses
In the months leading to the
solar eclipse of August 21, 2017
The solar eclipse of August 21, 2017, dubbed the "Great American Eclipse" by the media, was a total solar eclipse visible within a band that spanned the contiguous United States from the Pacific to the Atlantic coasts. It was also visible as a ...
, counterfeits of light-filtering glasses for solar eclipses began proliferating, leading to
public health
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...
issues. Effective eclipse glasses filter visible, ultraviolet, ''and'' infrared light.
The eye's retina lacks pain receptors, and thus damage could occur without one's awareness.
[ Includes photos of genuine and fake eclipse glasses.]
The AAS said determining whether an eclipse viewer was safe required a
spectrophotometer and lab equipment, but often the user should see nothing through the filter except for the Sun, sunlight reflecting off of shiny metal, or intense light sources such as an LED flashlight.
Andrew Lund, the owner of a vendor of eclipse glasses, noted that not all counterfeit glasses were necessarily unsafe. He stated to ''
Quartz
Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...
'' that the counterfeits he tested blocked the majority of harmful light, concluding that "the
IP is getting ripped off, but the good news is there are no long-term harmful effects."
On July 27, 2017, Amazon required all eclipse viewing products sold on its website have a submission of origin and safety information, and proof of an accredited ISO certification. In mid-August 2017, Amazon recalled and pulled listings for eclipse viewing glasses that "may not comply with industry standards", and gave refunds to customers who had purchased them.
See also
*
Astronomical solar filter
*
Eclipse chasing
*
Solar telescope
*
Transit of Mercury
*
Transit of Venus
frameless, upright=0.5
A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and a superior planet, becoming visible against (and hence obscuring a small portion of) the solar disk. During a tra ...
References
{{Eyewear
Eyewear
Ophthalmology
Prevention
Fashion accessories
Solar viewing glasses
2010s fashion