Monday’s total solar eclipse was incredible, but it may have left viewers with some undesirable side effects. Even if you properly protected your eyes while watching the event, you might be feeling a headache or a bit of nausea right now. Here’s everything you need to know about those reactions.

The most important thing: They’re normal. Headaches can be triggered by looking at a screen for too long, fluorescent lights, and other kinds of light exposure, including bright sunlight. People with “photophobia” are particularly sensitive to light and often get these symptoms, but even if that doesn’t apply to you, it’s still normal to be experiencing them after looking at an eclipse. The sun, even when it’s behind the moon, is bright enough to destroy retinal tissue and certainly to cause a headache.

So if you are experiencing a headache — which itself can cause nausea — that’s not in itself a cause for concern. It does not mean that you damaged your eyes during the eclipse, which seems to be a concern shared by many people on social media.

Research about why light can cause headaches is ongoing. A 2010 study on migraines found that “the perception of migraine headache […] is uniquely exacerbated by exposure to light,” and that people with a sensitivity to light had signals running between their retina (the light-sensitive back layer of your eyes) and optic nerve (the nerve that transmits information between the eye and brain) seconds after they got that exposure, and that it lasted for 20 to 30 minutes.

If you were looking back and forth between the eclipse and other, darker spots, that’s called “flickering,” and it could also have helped cause a headache.

At this point, the best thing you can do to mitigate your headache is to rest your eyes, if possible, and take some pain meds. In other words, a fairly standard treatment.

It’s no fun, but a post-eclipse headache is nothing to worry about.


You've read that, now watch this: "Nasa Explains How To Safely Watch A Solar Eclipse"