Something very similar happened to me. About 15 or so years ago I went for an eye exam and the doctor told me I had a "huge" optic nerve cup, which I was either born with or was a sign of glaucoma. They took a photo of my optic nerve (both eyes) - this was back in the day where I had to go to a special eye lab and then wait a month (!!!) for the results. As it turns out, this was something I was born with - my eye pressure is borderline so I am checked every 9 months, but so far, so good.