This can be caused by aging, diabetes, or nothing at all. They're believed to only be a concern when they happen very quickly and flood your field of vision without letting up %u2013 in those cases, you may have a retina problem. It's also something that occurs very often in those that have migraines. This is especially important for people with anxiety %u2013 anxiety does tend to trigger symptoms of migraines. Sometimes these will occur with headaches, but there are also "silent migraines" that occur with no headaches at all, and these too many cause visual symptoms.