The intense light of the sun, even during a solar eclipse, can cause permanent and irreversible damage to the eyes. Viewing the sun directly, even for a moment, without specialized protection risks solar retinopathy, a condition where the sun’s rays burn the sensitive tissue of the retina. Proper eye protection, specifically designed solar viewers, is a necessity for safe observation. Standard sunglasses are insufficient and cannot block the harmful levels of invisible ultraviolet and infrared radiation that the sun emits.
Essential Safety Standards for Eclipse Glasses
A pair of eclipse glasses is only safe if it meets the specific requirements of an international safety standard. This established guideline is known as ISO 12312-2, which is an international certification for filters used in direct solar observation. Compliance with this standard ensures the glasses reduce the sun’s brightness to a tolerable level and, most importantly, block 100% of the sun’s harmful ultraviolet and infrared radiation.
The specialized lenses in certified glasses are thousands of times darker than the darkest conventional sunglasses, often utilizing a black polymer or a reflective metalized film. This filter material must meet strict criteria for luminous transmittance, meaning only a tiny fraction of visible light is allowed through. The ISO 12312-2 marking confirms that the product has undergone rigorous testing to guarantee this necessary protection against high-energy visible light and invisible radiation.
Major National Retailers and Certified Online Vendors
The most reliable places to purchase safe solar viewers are through vendors vetted by experts in the field. The American Astronomical Society (AAS) maintains a list of reputable manufacturers and dealers who produce or sell ISO 12312-2 compliant products. Purchasing from a company on this list significantly reduces the risk of acquiring a counterfeit product.
Many major national chains often stock AAS-approved glasses as an eclipse approaches, including large retailers like Walmart, Lowe’s, and H-E-B. Specialized science and camera equipment stores, both physical and online, are also dependable sources for certified glasses. When purchasing from large online marketplaces, it is imperative to check that the seller is specifically named on the AAS list, as these platforms can host unauthorized third-party vendors.
Local and Community Distribution Points
For last-minute needs or free access, local and community organizations are excellent alternative sources for safe eclipse glasses. Public libraries often receive grants or bulk donations that allow them to distribute certified viewers to the public at no cost. These distribution programs are common in areas within or near the path of totality for a major eclipse event.
Local science museums, planetariums, and university astronomy departments frequently serve as distribution hubs for certified glasses. These educational institutions prioritize safe viewing and generally source their viewers from AAS-approved vendors. Additionally, local astronomy clubs and organizations hosting official public viewing events usually provide safe eclipse glasses to attendees, sometimes for free or a minimal donation.
Recognizing and Avoiding Counterfeit Products
The marketplace is often saturated with counterfeit products claiming to be safe, making verification a necessary step before use. A clear warning sign is a lack of crisp, legible certification markings, or an absence of the manufacturer’s name and address printed on the glasses. If the price seems unusually low, especially when buying in bulk, it should raise suspicion, as compliant manufacturing involves precise, verifiable processes.
The appearance of the filter material itself can indicate a fake product. When wearing the glasses indoors, you should not be able to see anything at all, with the possible exception of extremely bright lights, which should appear very faint. If you can see objects like furniture or walls, the glasses are not dark enough and are unsafe for sun viewing. Before using any viewer, inspect the lenses for scratches, pinholes, or tears in the film, as any damage compromises the filter’s integrity and makes the glasses dangerous.