Eye floaters are small specks, threads, or cobweb-like shapes that appear to drift across your vision. They are particularly noticeable when looking at a plain, bright background, like a clear sky or a white wall. These visual phenomena are common and, for most individuals, are a harmless part of the eye’s natural aging process.
What Are Eye Floaters
Eye floaters are tiny pieces of debris suspended within the vitreous humor, the clear, jelly-like substance that fills the space between your eye’s lens and retina. These microscopic clumps of protein or other cellular material cast shadows directly onto the retina, the light-sensitive tissue at the back of the eye. This shadow is what you perceive as a floater.
Floaters move as your eye moves, and if you try to look directly at them, they seem to dart away, only to drift back into view when your gaze is still. This movement is due to their suspension within the vitreous gel, which allows them to shift with the eye’s motion. They are not optical illusions but are entoptic phenomena, meaning they are caused by structures within the eye itself.
Common Causes of Floaters
The most frequent cause of eye floaters is age-related changes in the vitreous humor. As people age, the vitreous can shrink and become more liquid, a process known as vitreous syneresis. During this process, the collagen fibers within the vitreous can clump together, forming the visible floaters.
This natural aging process often leads to posterior vitreous detachment (PVD), where the vitreous gel pulls away from the retina at the back of the eye. PVD affects about 75% of people by age 65. While PVD itself is benign, the separation can create new floaters or make existing ones more noticeable.
When Floaters Are a Concern
While a few stable floaters are normal, certain changes warrant immediate medical attention. A sudden increase in the number of floaters is a concern. This includes “showers” of tiny new floaters.
Flashes of light, known as photopsias, occurring alongside new floaters are a concern. These flashes appear as lightning streaks or camera flashes, particularly in peripheral vision. Additionally, the appearance of a dark curtain or shadow moving across your field of vision, or a sudden loss of side vision, signals a potential emergency.
Serious Conditions Linked to Floaters
The concerning symptoms of new or increased floaters, flashes of light, or a dark visual curtain can be linked to several serious eye conditions. One such condition is retinal detachment, where the retina pulls away from the back of the eye. This can occur if the shrinking vitreous gel tugs on the retina with enough force to create a tear, allowing fluid to accumulate behind it. Untreated retinal detachment can lead to permanent vision loss.
Another cause is vitreous hemorrhage, which is bleeding into the vitreous humor. This can result from conditions like diabetic retinopathy, high blood pressure, blocked blood vessels, or eye injury, and the blood cells appear as floaters. Inflammatory conditions like posterior uveitis, an inflammation in the back of the eye, can also cause floaters by releasing inflammatory debris into the vitreous. Prompt diagnosis and treatment preserve vision.