To safely watch a solar eclipse, you must use special‑purpose solar filters or eclipse glasses that meet the international safety standard ISO 12312‑2. Regular sunglasses, even very dark ones, are not safe for direct‑sun viewing and can still cause serious eye damage.

What makes eclipse glasses “safe”

  • The glasses must be explicitly labeled as compliant with ISO 12312‑2:2015 (or 12312‑2) on the lenses or packaging.
  • They must block nearly all visible sunlight , transmitting no more than about 0.00032% of the Sun’s light , plus harmful UV and infrared radiation.
  • The material should be free of scratches, bubbles, or dents ; if any of these are present, the glasses should be discarded.

What to look for when buying

When people ask “what glasses are safe for solar eclipse,” eye‑safety and astronomy groups emphasize the same basics:

  • Buy from reputable vendors or manufacturers that explicitly state ISO 12312‑2 certification; avoid homemade or unbranded filters.
  • Boxes or labels should include: manufacturer name, instructions for use, and warnings (e.g., “for direct solar viewing only”).
  • If you already have a pair, check that they are not old, scratched, or from an unknown source ; many organizations recommend discarding older or questionable viewers.

What is not safe

  • Regular sunglasses (even polarized or very dark ones) are far too bright for eclipse‑viewing and can still let through enough sunlight to injure your retina.
  • Camera‑film, CDs, smoked glass, or improvised filters are unsafe and can cause permanent “eclipse‑burn”‑type retinal damage.
  • Wearing regular glasses underneath eclipse glasses (like prescription glasses) is fine, as long as the outer filter itself is ISO‑certified and undamaged.

Quick‑reference table

Item| Safe for eclipse?| Notes
---|---|---
ISO‑12312‑2‑certified eclipse glasses| Yes ✅| Must be undamaged and from a reputable vendor. 257
Regular sunglasses (any darkness)| No ❌| Even very dark ones transmit too much light. 136
Camera‑film, smoked glass, CDs| No ❌| Can still transmit harmful wavelengths. 59
Homemade or unbranded filters| No ❌| Risk of serious retinal injury. 27

Quick viewing tips

  • Put the glasses on before you look toward the Sun; remove them only after you have turned away.
  • During a total solar eclipse , it is only safe to remove the glasses in the brief “totality” phase when the Moon completely blocks the bright face of the Sun; as soon as the Sun starts to re‑appear, glasses must go back on.

If you tell me where you plan to view the eclipse (e.g., April 8 corridor vs. another date), I can suggest a few current‑season brands or where to buy certified glasses in your region. Information gathered from public forums or data available on the internet and portrayed here.