Wednesday's eclipse poses a significant public health risk

European health authorities are urging people to take precautions to watch Wednesday’s solar eclipse safely, as counterfeit viewing glasses circulate and legitimate supplies sell out.

Millions of people are waiting to observe a partial or total solar eclipse – when the moon covers the sun completely – in most of mainland Western Europe, the first since 1999. But without the protection of certified eclipse glasses, the phenomenon also poses a significant public health risk.

Spanish authorities withdrew six viewing glasses from the market on Monday due to injury risks. However, a government surveillance campaign noted that most of the glasses it analysed had strong overall compliance with information and material standards for frames, lenses and coatings.

“Direct exposure to the sun can cause solar retinopathy, a retinal lesion that is often painless but can lead to irreversible visual complications,” warned the French Society of Ophthalmology. In the most serious cases of overexposure, this can lead to forms of blindness.