Once or twice a year, Brooke Baldwin is hit with a “debilitating” migraine. More than just a simple headache, the host is stuck down by ocular migraines which, is the reason Baldwin, 39, suddenly disappeared from hosting her CNN room show Thursday afternoon. “I got my first migraine on my first day of work in TV in 2001… it was debilitating,” Baldwin tells PEOPLE. “Since then, they’ve gotten ‘better.’ They’re ocular meaning I know they come on because my vision instantly starts to blur (try being under tons of TV lights and staring into a TelePrompter — yikes),” Baldwin continued. “I get an ‘aura’, which is the sign I need to act fast and stop everything I’m doing,” Baldwin explains. After the migraine comes on, Baldwin must immediately take her medicine before finding a dark room to rest and close her eyes. She says after that, she’s “generally okay,” but “light sensitive for the rest of the day.” “It’s scary, but I’m fortunate they don’t happen way more often or make me nauseous,” the news anchor added. Thursday’s incident left many viewers concerned for Baldwin. She was in the middle of her segment when the show went to commercial break. When her program returned, viewers were surprised to see Brianna Keilar, host of CNN Right Now, which airs weekdays fromtop.m. ET, covering the segment instead. Baldwin later resurfaced on social media to explain why she disappeared. “Ocular migraine. I get ’em about once a year. And in 20 years of doing live TV… that had never happened on set til today. I suddenly couldn’t see. HUGE props to my girl @brikeilarcnn for hopping in the seat withmins notice,” Baldwin tweeted. Baldwin was back on air Friday and announced her return on social media after a fan wrote, “@CNN My girl @BrookeBCNN is back. Don’t scare us like that anymore.” “Glad to be back. And thank you!” Baldwin tweeted. American Migraine Foundation describes an ocular migraine as a term used to describe a number of migraine “subtypes that are characterized by a variety of visual disturbances including visual loss, blind spots, zig-zag lines, or seeing stars.” Ocular migraines that cause vision disturbance are often caused by harsh lights, electronic screens or straining your eyes for long periods of times.