Friday, between 9.45 am and 11.15 am, a total solar eclipse will be partially visible in all of the countries of Europe. In France, the obscuration of the sun will be 58 to 83% depending on the location, but there is no question of looking at this phenomenon directly because, even if the light is reduced, the solar radiation is still just as intense. In fact, looking at a solar eclipse is as dangerous as looking at the sun directly, unprotected.
What are the risks if we do not protect ourselves properly?
As we are not dazzled, this encourages us to observe the eclipse without adapted glasses, which amounts to concentrating all the rays emitted by a point of the sun on a point of the retina. This may cause corneal lesions, very painful but fortunately reversible in a few days, or retinal burns related to the direct effects of infrared on the retina.
“It only takes a few seconds of exposure for the macula, the central part of the retina responsible for 80% of visual acuity, to be irreparably burned. The resulting lesion results in a black spot, a negative image. of the sun, imprinted on the retina for life, ”explains Annie Rodriguez, Director of Vision Health at Essilor. “This danger is all the more insidious since the burn is quite painless. It is only a few hours after exposure to the sun that one begins to feel a violent headache”.
These burns during an eclipse cause a decrease in central vision and color vision, visual distortions and the perception of a dark spot in the center of the field of vision.
What should be avoided at all costs?
– Do not observe the eclipse directly, nor through a glass plate blackened by smoke or sunglasses because this does not sufficiently attenuate the intensity of the radiation from the direct light source which is the sun (and in particular infrared rays).
– Do not use binoculars or telescopes which will aggravate the danger to the eyes.
– Protective glasses have been specially designed to look directly at the sun, with black polymer filters that provide a sharp image of the orange-colored sun. They filter 100% of ultraviolet rays, 100% of infrared rays, and 99.99% of light intensity.
These glasses are available from opticians, pharmacies or you can get the latest issue of the Science and Life magazine, still in kiosk, sold with a pair of adapted glasses.
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