Please Read this, I went through most of the symptoms the majority of the posters are writing about and I hope what I have to say can help you. By the way I am 19.
When I was 18 years old I started noticing these "sparkles, glitter. prickles, ect." looking up at a cloudy yet bright sky. I remember the first time I noticed them I thought literally nothing of them. I knew they were part of my vision but I guess I just didn't care.
About a year later I moved to a house on the beach and enjoyed taking long jogs on it at night, that was when they started bugging me. After an invigorating run they would be darting all over the place. After my day runs I would jog back into the house and than about five minutes later walk back out side and just stare up at the sky, I bet my neighbors thought I was a loony. Thoroughly freaked out I went to my neared medical resource, Dr. Firefox. I read dozens of yahoo answers and medical sites telling me that "Flashes (which i guess was a poor description of them on my part)" meant retinal detachment. Anyway this was the start of my career as a hypochondriac, and here are a couple things you should know about the symptoms you are experiencing.
1. As you age your body changes, experiencing new and frightening symptoms is a part of life. However this doesn't mean new symptoms should go ignored.
2. Just because you have one or two symptoms doesn't mean that you have the worst possible disease pertaining to those symptoms.
3. The darting sparkles perceived against a very light or dark background are blood vessels traveling through your eye, not floaters, once you start seeing floaters you will know the difference. Especially if they bug you most or increase in speed and prevalence immediately following exercise. My eye doctor told me the only time to worry about retinal detachment is if seeing through the effected eye is almost or completely impossible. Supposedly you need to be hit in the eye to detach your retina as well, it doesn't just budge loose.
4. Floaters are also natural.
The nice thing about floaters are that they eventually settle to the bottom of your eye. And if they are really bothering you, there are lasic procedures that can obliterate them. Again the only time to really worry about them is if you see a whole swarm of them, and not just a a clump but a swarm of clumps encompassing the majority of your vision.
5. Ringing in your ears, there are a few causes for this an just because you have it doesn't necessarily mean that you will have it permanently. Allergies can cause ringing in your ears, if glands or sinuses are swollen they can put unnecessary pressure on your ear canal which your drums and brain perceive as sound. Sinuses can also put pressure on your eyes which could be a possible cause for some of the symptoms people are experiencing. Also my communications professor keeps ranting about how generation y, a.k.a. us are going to be deaf by the time we are 35. And he has studies to back it up, ask someone in their forties if they have ringing in their ears a.k.a. tinnitus and the majority of them will tell you a definitive yes. Partially due to being the first generation of people exposed to electronically amplified sound.
6. Don't walk around trying to notice your symptoms. I went through this phase and let me tell you, as soon as you stop trying to notice them they all but disappear. One poster suggests that if you train your eyes not to focus on the sparkles (blood vessels) eventually you will stop perceiving them. I haven't gotten that far, but what I will say is that since I stopped walking around looking at the sky all the time I have stopped seeing floaters completely (knock on wood) and only see the sparkles when I take a forbidden glance up into the sky to see if they are still there. But I suppose that is why so many people wear sun glasses...
7 (last one) . If you haven't seen a doctor than maybe you should, not just to make sure you aren't seriously injured, but to give you peace of mind. If you have seen a doctor on multiple occasions and they tell you everything is fine, chances are it probably is. If you notice something new give 'em a call but otherwise find ways to deal with your symptoms on your own, a few of mine are...
Taking allergy medication, and reducing the things that make me allergic on a daily basis.
Taking breaks from the computer, which can stress they eyes, and stress and anxiety can and do cause noticeable symptoms. (Which sucks because than you get anxious about the symptoms...)
Using eye drops a few times a day. My eyes tend to get dry which can cause vision to be blurry and sometimes halos around lights. (It takes about two weeks of using drops to re-lubricate the lenses of your eyes.)
Taking a daily vitamin. Your eyes need vitamin a to function properly so eating apples and bananas daily can help.
I hope this information has been helpful and if you still aren't noticing positive changes in your symptoms, keep looking for answers an solutions to your problems , you will find them eventually.
-James