Hillary Clinton's glasses are big and bulky, and they're helping the Secretary of State in her recovery from a concussion and blood clot she suffered.
Viewers got a chance to see Hillary Clinton's glasses during the more than five hours of testimony she gave before Congress on the handling of the Benghazi incident.
"She'll be wearing these glasses instead of her contacts for a period of time because of lingering issues stemming from her concussion," said spokesman Philippe Reines told ABC News. "With them on she sees just fine."
Reines didn't get into specifics, but experts say Hillary Clinton's glasses likely have a fresnel prism. This is a piece of thin, transparent plastic that changes the way lights enter the eye, commons used to treat double vision.
Dr. James Liu, director of the Center for Skull Base and Pituitary Surgery at the Neurological Institute of New Jersey, said concussions have been known to lead to double vision that can last for quite some time.
"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."
Hillary Clinton's glasses were a subject of discussion after her Benghazi testimony. New York Magazine published a slideshow of Clinton adjusting her glasses as her testimony often grew heated, inserting pithy comments with each picture.