Why is Hillary Clinton wearing glasses?

US Secretary of State Hillary Clinton has been wearing thick-rimmed eyeglasses since returning to work on Jan. 7 after recovering from a concussion and being treated for a blood clot between her brain and skull.

It’s well known that Clinton, who sported large glasses during her college years and owns pantsuits in every color of the rainbow, wears what she likes.

In a 2012 interview with CNN she said, "I feel so relieved to be at the stage I'm at in my life right now. Because you know if I want to wear my glasses I'm wearing my glasses. If I want to wear my hair back I'm pulling my hair back. You know at some point it's just not something that deserves a lot of time and attention.”

But Clinton is not making a sartorial statement with her current glasses-wearing, her spokesman Philippe Reines said today, according to ABC News.

"She'll be wearing these glasses instead of her contacts for a period of time because of lingering issues stemming from her concussion," he said. "With them on she sees just fine."

James Liu, director of the Center for Skull Base and Pituitary Surgery at the Neurological Institute of New Jersey, told ABC News that concussions and head injuries can cause cases of blurred or double vision.

"It is possible that blurred or double vision can last up to weeks and even months," he said. "This really depends on the severity of the head injury. In cases of concussions, these symptoms are usually temporary and eventually resolve with time."

While Reines did not provide details about Clinton’s current glasses, the left lens of Clinton’s specs appears to have a Fresnel prism affixed to it, experts told the New York Daily News. Fresnel prisms – they look like clear stickers with transparent lines etched into them – are used to treat double vision.

More from GlobalPost: Hillary Clinton's 11 best memes and moments
 

Will you support The World with a monthly donation?

Every day, reporters and producers at The World are hard at work bringing you human-centered news from across the globe. But we can’t do it without you. We need your support to ensure we can continue this work for another year.

Make a gift today, and you’ll help us unlock a matching gift of $67,000!