Special glasses needed to safely view the eclipse
Glasses made specifically for looking at the sun offer the only safe way to view the eclipse directly.
“Eclipse glasses are very important to prevent photothermal injury to the retina, and not just any old glasses — they have to be eclipse glasses with the ISO 12312-2 filter,” said Dr. Nicole Bajic, a comprehensive ophthalmologist at the Cleveland Clinic Cole Eye Institute.
The glasses are “thousands of times darker” than sunglasses, according to NASA.
Without such precautions, watching the eclipse can cause permanent eye damage.
“It’s called solar retinopathy, and it’s damage to very sensitive, intricate cells that make up the retina, which is the lining of the back of the eye, and that’s what transmits light into electrical signals so that we can see what we see,” Bajic said. “And when we have damage from the sun to that tissue, we can get decreased vision and central blind spots in our vision.”
What is a total solar eclipse?
Today’s cosmic event is one of two types of eclipses: lunar and solar. So what makes a solar eclipse? NBC News’ Zinhle Essamuah explains:
Your last-minute guide to the total solar eclipse
A total solar eclipse will cross North America today, offering millions a rare opportunity to see afternoon skies temporarily darken as the moon blocks the face of the sun.
Need to catch up quick? This guide will tell you what you need to know, including fun milestones to look for if you’re lucky enough to be in the path of totality and how to view the eclipse safely.
It's finally here!
Good morning and happy Great American Eclipse Day!
Our live updates throughout the day will include reporting from across NBC News as the eclipse crosses the country.