Eclipse Glasses: Certified Filters vs Sunglasses

Disclosure: This guide may contain affiliate links. If we add them, buying through those links could earn the project a small commission at no extra cost to you. It never changes which products we describe as safe — certification, not commission, decides that.

Why sunglasses are never enough

It is tempting to assume that very dark sunglasses, or several pairs stacked together, must be "dark enough." They are not. A certified solar filter transmits roughly one hundred-thousandth of the visible light that even the darkest sunglasses let through, and it also blocks the intense infrared and ultraviolet that sunglasses ignore. The danger is compounded by the fact that the retina has no pain receptors: you can burn it without feeling a thing, and the damage — solar retinopathy — can be permanent. Stacking sunglasses, using exposed film, smoked glass, or CDs does not work and is not safe.

What "ISO 12312-2" actually means

ISO 12312-2 is the international safety standard for filters used to look directly at the Sun. A filter that genuinely meets it reduces the Sun's brightness to a safe, comfortable level and blocks harmful infrared and ultraviolet across the required range. The key phrase is genuinely meets it: printing the number on a sleeve costs nothing, so the standard is only as good as the manufacturer behind it.

How to verify your glasses are genuine

• Real maker, real address. Certified glasses carry the manufacturer's name and a physical address, not just a logo.
• The "nothing but the Sun" test. Indoors, you should see essentially nothing through them — ordinary room lights should be invisible or barely visible. Only the Sun, or a comparably intense lamp, should show through.
• No damage. Hold them to a bright light and check for scratches, pinholes, dents, or separation of the filter from the frame. Any damage means discard them.
• Trusted source. Buy from an accredited manufacturer or a retailer that lists one, not an anonymous marketplace seller.

Counterfeit warning signs

Counterfeit and substandard glasses flood the market before every major eclipse. Treat these as red flags:

• No manufacturer name or address printed on the glasses.
• An ISO 12312-2 claim presented as marketing text with no identifiable maker behind it.
• You can clearly see indoor lighting, your phone screen, or surroundings through them.
• Visible scratches, creases, wrinkles, or pinholes in the filter material.
• Implausibly cheap bulk listings, or a seller with no track record.
• Packaging that misspells the standard or copies branding from a known maker.

If a pair fails any of these checks, do not use it. Replacement glasses are inexpensive; an eye injury is not.

Accredited manufacturers

The following manufacturers are widely recognised for producing genuinely certified solar viewers. Buying their products directly, or from retailers who stock them, is the simplest way to avoid counterfeits:

• American Paper Optics — one of the largest makers of certified paper eclipse glasses.
• Rainbow Symphony — long-established maker of certified solar viewers and filters.
• Celestron — certified glasses plus solar filters for telescopes and binoculars.

Telescopes, binoculars and cameras

Eclipse glasses protect your eyes only. Never look at the partial Sun through an unfiltered telescope, binoculars, or camera viewfinder — the optics concentrate the Sun's heat and will cause instant, severe injury even while wearing eclipse glasses. Any optical instrument needs a dedicated front-element solar filter rated for the job. The filter goes on the front of the instrument, never on the eyepiece.

The one moment you can take them off

During totality — and only during totality, when the Moon completely covers the Sun's bright disk — it is safe and necessary to remove your filter to see the corona with the naked eye. The instant the first sliver of the photosphere reappears, the filters must go back on. If you are outside the path of totality, that moment never comes, and the filters stay on the entire time. Check your location and totality window on the interactive map.

Frequently asked questions