Health authorities and astronomers are warning the public to use only certified solar-viewing glasses to avoid permanent eye damage during solar eclipses.

Improper eye protection can lead to irreversible vision loss because the eyes are exposed to intense solar radiation. With several eclipse events occurring in Spain and South America, experts are emphasizing the danger of improvised filters.

Authorities, including the Instituto Geográfico Nacional and NASA experts, said that only glasses certified to the ISO 12312-2 standard [4] are safe for viewing. They said that welding masks, radiography plates, and other improvised filters are not suitable for this purpose [1, 3].

These warnings come as the region prepares for multiple events. A total solar eclipse was visible across the Spanish peninsula on Aug. 12, 2024 [1], and an annular eclipse occurred on Oct. 2, 2024 [2]. The most recent total eclipse visible in Spain had occurred in 1912 [1].

Attention is now turning toward the total eclipse expected in August 2026 over Aragón, Spain. This event is expected to attract 400,000 visitors [1] to the region. Because of the high volume of tourists, officials are concerned about the prevalence of counterfeit or substandard eyewear.

La Sexta editorial said that the risks are immediate, stating, "A ojo desnudo, no mirar ni un segundo" [6]. This translates to a warning against looking at the sun with the naked eye for even one second.

Experts said that many people mistakenly believe welding-type filters work, but these do not provide the necessary protection against the specific radiation emitted during an eclipse [3]. To ensure safety, consumers are advised to verify the ISO certification on the product packaging before use.

“A ojo desnudo, no mirar ni un segundo.”

The recurrence of solar eclipses in Spain, particularly the high-traffic event expected in Aragón in August 2026, creates a public health risk due to the availability of non-certified eyewear. The insistence on the ISO 12312-2 standard highlights that general light filtration is insufficient; only specific optical certifications can prevent solar retinopathy during these events.