Floaters in the vitreous of the eyeball (aka clumps of your vitreous that got stuck together as your vitreous gel started to liquify, which happens naturally with age for everyone).

They're normal if they appear gradually as you age. Most common in people with myopia. Can be caused by a variety of things including hits to the eyes or head, possibly by steroid eye drops, anything that increases the pressure in your eye, or just plain old aging.

They never go away but if you're lucky they might "settle" or get stuck to the side. Never happens for a lot of people though, and they can be quite distressing for many people - especially for people who have many large and moving floaters.

Most mentally healthy people will neuro-adapt and they'll become less noticeable over time. It can take about six months before this happens though and it does suck at first. I got some new ones after LASIK and I was pretty upset. Now I only notice them on light backdrops like snow or my shower. But even then I just notice them briefly and my thoughts quickly move elsewhere. No stress.

For people who are absolutely driven insane by a large number of them, there is a risky surgery to remove them, but if it goes wrong you can be looking at blindness so you definitely need to weigh your options.

The non-surgical laser treatment for floaters doesn't work. It seems to maybe work for some people in the short term but most people report that it doesn't help in the long term. It can even create more floaters or break up your big ones into many smaller ones that move more. The laser is also dangerous for younger patients because the floaters are closer to your retina when you're younger. The laser can cause damage to the retina and it's hard to avoid doing that when the floaters are close to it.

There are currently a couple groups researching how to get rid of them non-invasively. Last bit of news I saw said a group had been using gold flakes and a new type of laser to successfully and safely break them down. Personally, I will get mine treated if there is a non-invasive way to do so, but I'm not too bothered by them so I can wait for that.

Worth noting that if you suddenly get a lot of floaters and are feeling pain in your eyes or seeing bright flashes that look like a camera flash, you need to go seek medical attention immediately as these are signs of a retinal tear. Retinal tears are treatable but only if you go take care of them immediately. The consequences are not taking care of them quickly can be severe.

For most people, these are harmless and just a part of getting older. You'll get used to them.