If you’ve ever noticed small, dust-like specks or squiggly lines floating around in your field of vision, you have eye floaters. Tons of people have them, and they’re completely normal. Most of the time, while they can be annoying, they’re also nothing to worry about.
“Floaters are a normal phenomenon in the eye that happens as people grow older,” Stephen Anesi, M.D., physician at Massachusetts Eye Research and Surgery Institution, tells SELF. “They’re a process of the eye changing normally.”
Here’s what’s going on in your eye when you see floaters, and how to know if they’re a sign of a bigger problem.
Floaters happen when the gel-like substance in your eye, called vitreous, changes as you age.
The main chamber of your eye is filled with vitreous, which is what helps the eyeball keep its shape. It’s clear, so that light can pass through it and reach the retina, and is made up of mostly water with some collagen, salt, and sugar. As you age, “vitreous stays clear, but the consistency becomes more liquid,” Anesi says. At the same time, microscopic fibers and cells in the vitreous tend to clump over time, and when the light hits them, it casts small shadows on your retina. Those shadows are what you’re seeing.
When the vitreous is more liquidy, “it becomes more mobile inside the eye and can shift when the eye is always moving, causing some turbulence,” Anesi says. That’s what causes that floating effect—since the clumps are basically riding the waves inside your eyeball. It’s also why the spots seem to scurry away when you move your eye to look directly at them.
While most of the time floaters are absolutely nothing to worry about, a dramatic change in the amount you see can be a sign of a serious problem.
“That’s the reason we always dilate the eyes fully and do an exam when someone complains of floaters,” Anesi says. It’s especially worrisome if an increase in floaters is paired with a flash of light, which can signal retinal detachment. You can’t feel retinal detachment happening so it’s important to heed these warnings.
A detachment typically requires immediate surgery, or else it can leave you with lasting vision problems and even blindness. Sometimes, floaters and flashes that occur together are not immediately problematic. An eye exam can determine whether or not it’s a real issue, and your doctor may just ask to see you more regularly to make sure that it doesn’t progress into something worse.
Bleeding in the eye, which is more likely in those with diabetes or very high blood pressure, can also cause floaters, as can an infection (deep inside the eye, not something on the surface like pink eye) or an autoimmune condition that causes inflammation in the eye.
You should always go see your eye doctor when there’s a large change to determine whether there’s a serious problem. If your floater situation stays pretty status quo, there’s no need to bat an eyelid.