International Tennis Hall of Famer Monica Seles was diagnosed with myasthenia gravis three years ago, she revealed Tuesday.

Seles, 51, publicly discussed her diagnosis in an interview with The Associated Press. Myasthenia gravis is an autoimmune condition that affects how your nerves communicate with your muscles and causes muscle weakness that worsens throughout the day with activity, according to the Cleveland Clinic. Double vision and/or drooping eyelids are often the first symptom, per the Clinic.

“I would be playing with some kids or family members, and I would miss a ball. I was like, ‘Yeah, I see two balls.’ These are obviously symptoms that you can’t ignore,” Seles told AP. “And, for me, this is when this journey started. And it took me quite some time to really absorb it, speak openly about it, because it’s a difficult one. It affects my day-to-day life quite a lot.”

Seles, a nine-time Grand Slam winner, said she is speaking publicly about her diagnosis to raise awareness around “MG” ahead of the U.S. Open, which begins Aug. 24 in New York City. Seles previously won the French Open in consecutive years in 1991 and 1992. She told AP she was unfamiliar with myasthenia gravis until she saw a doctor and was referred to a neurologist. In addition to double vision, she also noticed symptoms including weakness in her arms and legs.

Seles won her first Grand Slam title at age 16, winning the 1990 French Open at Roland Garros, and last played at the same event in 2003. She officially retired from professional tennis in 2008.

Aside from her on-court success, Seles became infamous for a 1993 incident in which a fan stabbed her in the back with a knife during a match against rival Steffi Graf in Germany. She was taken to the hospital and recovered from her injuries.

Seles, a native of Serbia (formerly Yugoslavia), said she views her MG diagnosis as yet another “reset” in her career and life.

“I had to, in tennis terms, I guess, reset — hard reset — a few times,” Seles said. “I call my first hard reset when I came to the U.S. as a young 13-year-old (from Yugoslavia). Didn’t speak the language; left my family. It’s a very tough time. Then, obviously, becoming a great player, it’s a reset, too, because the fame, money, the attention, changes (everything), and it’s hard as a 16-year-old to deal with all that. Then obviously my stabbing — I had to do a huge reset.

“And then, really, being diagnosed with myasthenia gravis: another reset. But one thing, as I tell kids that I mentor: ‘You’ve got to always adjust. That ball is bouncing, and you’ve just got to adjust. And that’s what I’m doing now,” she added.

“Myasthenia gravis affects about 20 out of every 100,000 people around the world, according to the Cleveland Clinic,” said Julie Washington, health reporter for cleveland.com and The Plain Dealer. “The Clinic says there are approximately 60,000 people affected by myasthenia gravis at any given time.”

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