Why Do We See Floaters?
You notice them against a bright sky or a blank white page: specks, threads or little cobwebs that drift when you move your eyes and dart away when you try to look straight at them. Almost everyone sees floaters at some point. They feel like dust on your eye, but they are actually inside it, and what you see is not the object itself but its shadow.
A gel that is mostly water
The inside of your eyeball is filled with the vitreous, a clear gel that is about 98 to 99 percent water held in shape by a fine scaffold of collagen fibers and a sugar molecule called hyaluronan. In a young, healthy eye this gel is remarkably transparent, because the collagen is spread out evenly and is far too thin to see.
With age, and earlier in people who are nearsighted, the chemistry shifts. Collagen starts to separate from the hyaluronan and the fibers clump together into strands. The gel also slowly liquefies in patches. Those clumped fibers are large enough to scatter light, and light scattered on its way to the retina casts a shadow. That moving shadow is the floater you see.
Why they drift and dart
The vitreous is a gel, not a liquid, but it is not fully rigid either. When your eye moves, the gel sloshes slightly, and the clumps inside drift with it, which is why floaters seem to float past and then keep gliding for a moment after your eye stops. They dart away when you look at them because the clump sits off to the side of your central vision; turning your eye toward it moves the gel again, so the shadow slides away. It is a bit like trying to look directly at a speck suspended in jelly.
The common big change: the gel pulling away
The most common cause of a sudden new floater is a posterior vitreous detachment. As the gel shrinks with age, it can peel away from the retina, and the dense back surface of the gel becomes visible as a large floater, often described as a ring or a big cobweb. This is usually harmless in itself, and the brain is good at learning to tune floaters out over months.
One warning matters though. A sudden shower of many new floaters, especially together with flashes of light or a dark curtain at the edge of vision, can mean the shrinking gel has torn the retina. That needs an eye exam quickly, because a retinal tear is treatable and a retinal detachment is an emergency.
Can anything be done?
For most people the answer is simple: nothing needs to be done, and the floaters fade from awareness as the brain adapts. For the minority whose floaters are dense and genuinely disruptive, ophthalmology offers two options, each with trade-offs: a vitrectomy, surgery that removes the gel, or a laser procedure that breaks large clumps into smaller ones. Reviews of the evidence describe carefully selected surgery as effective, but doctors weigh it cautiously because operating on a healthy eye carries real risk.
Facts checked: October 26, 2026
Sources: Milston, R., Madigan, M. C., and Sebag, J. (2016). Vitreous floaters: Etiology, diagnostics, and management. Survey of Ophthalmology. Albrecht, M., Auffarth, G. U., Friedrich, M., Kessler, L. J., and Khoramnia, R. (2025). Vision degrading myodesopsia from vitreous floaters in the young. Survey of Ophthalmology. Boneva, S. K. et al. (2025). Clinical Management of Vision Degrading Myodesopsia from Vitreous Floaters. Ophthalmology. Retina.