Hi metagirl. Not to freak you out, but based on what little knowledge I myself have on seeing stars and what my ophtalmologist told me, I do recommend that you give yours a call. Please bear in mind I'm no expert, and can only tell you my own story. Before you read it, also know that I sincerely believe there may be several other explanations for seeing stars than the one reason I'm familiar with myself.
This is what happened to me: I saw stars for a while, and later on these 'floaters' that WendyS mentions. Eventually (months after the symptoms set in) I finally got an appointment with the ophtalmologist, she examined my eyes and told me I had... hm, I have no idea what the diagnosis is in English! But there's a great part of the eye that in Latin is known as the corpus vitreum (I'm sure you'll find it on the internet), and as we grow older this part of the eye sort of shrivels. That in itself is not a diagnosis, it's just ageing, but if you are terribly unlucky the shrivelling corpus vitreum may in a few cases pull at and tear the retina, and that may in turn cause the retina to sort of fall down or fold over - I'm not sure how to describe it in English, but as you can imagine, it's not a good thing, and you would certainly want to discover those tears before the retina collapses. To put it bluntly, the way I understand it you would lose your eyesight if that happened. But if there are tears and they are discovered in time, it can be fixed.
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