What causes eye floaters in a 19 year old? i have dealt with them for many years but they keep increasing. i saw 2 eye doctors who said retina was ok

You just do, unless?: Floaters commonly and gradually develop over ones' life, & are due to aging. They may be a nuisance, but adaptation to them is the norm. If the floaters arise from a sudden burst, with erratic light flashes &/or dark curtain blocking part of vision, then likely pathological. Otherwise floaters are observed. If you experience the above OR NEW changes, then seek an Eye MD for RE-evaluation.