Total solar eclipse: certified glasses or goodbye retina

Published on May 16, 2026 | Translated from Spanish

The National Geographic Institute, through Alejandro Asín, has issued a clear warning: the total solar eclipse on August 12 is not a spectacle to be taken lightly. Coinciding with the peak of the meteor shower, the event requires certified eye protection. Asín has advised against outdated methods still circulating, such as using X-rays or welder's goggles, noting that these homemade tricks can cause irreversible damage to eyesight.

Close-up photorealistic technical illustration of a human eye retina being damaged by unfiltered intense sunlight during a total solar eclipse, a pair of certified eclipse glasses with CE logo and ISO 12312-2 marking lying unused on a table nearby, discarded obsolete methods like an X-ray film and welding goggles in the background, dramatic high-contrast lighting showing the blinding solar corona edge, cinematic medical visualization, detailed anatomical structures, warning atmosphere with deep shadows

Solar filter technology: standards and certification 🌞

To safely observe the eclipse, glasses must comply with the ISO 12312-2 standard, which guarantees a filter capable of blocking 99.99% of visible light and infrared radiation. Unlike welder's filters of grade 14 or higher, whose protection spectrum is not designed for direct astronomical observation, certified lenses use an aluminum coating or specific optical polymers. Any scratch or defect in the filter renders it ineffective, so it is recommended to purchase them from official distributors, not from second-hand stores or street stalls.

X-rays and welders: the recipe for tears 😵

If anyone still thinks looking at the sun through a dental X-ray is a good idea, they should prepare to see the next episode of their favorite series blurry. The problem is not just that they don't filter enough light, but they also have the courtesy of letting UV rays through, just to fry the retina. And as for welder's goggles: yes, they work for an electric arc, but for an eclipse they are like using a colander to drink water. On August 12, it's best to follow Asín's advice: certified glasses or watch the event on YouTube.