The underlying cause is a gel-like substance inside the eye called the vitreous. As we age, the vitreous gradually liquefies, and the microscopic fibers suspended within it begin to clump together. Those clumps cast shadows on the retina, and those shadows are what the brain registers as floaters.
In some cases, floaters are linked to more serious conditions: eye infections, uveitis (inflammation inside the eye), or retinal tears and detachment. Certain groups face a higher baseline risk — people who are nearsighted, those who have undergone cataract surgery, and patients with diabetes, whose condition can lead to diabetic retinopathy.
The vitreous and the aging eye
The vitreous humour fills roughly 80% of the eye’s interior and is mostly water in younger people. With age, its gel structure breaks down and the collagen fibers within it aggregate — a process that begins for many people in their 40s and 50s. This natural degeneration is the primary driver of floaters in the general population.
Three symptoms that require immediate medical attention
Most floaters are benign and fade into the background over time. The concern arises when specific warning signs appear alongside them.
A sudden increase in the number of floaters, the appearance of flashes of light, or a dark curtain or shadow moving across peripheral vision can all indicate a retinal tear or detachment. These are medical emergencies: without prompt intervention, a detached retina can cause permanent vision loss.
Dr. Rick Ansorge is direct on this point: “If you experience any sudden changes in your vision, seek medical advice immediately.” The window for effective treatment is narrow, making early recognition of these symptoms critical.
