What are eye floaters?
Eye floaters are a visual phenomenon caused by opacities and light scattering in the vitreous gel at the back part of the eye that cast shadows onto the surface of the retina. These opacities cause annoying linear shadows or dark spots that move with eye and head movement. Eye floaters can come on suddenly or gradually. Due to their proximity to the retina, the brain can interpret the floaters as being quite large. Each patient will perceive eye floaters differently and will be bothered by them by varying degrees. The Latin origin of the word floaters is “muscae volitantes” or “flying flies,” a description that many patients that suffer from floaters find particularly fitting.
Why do floaters occur?
To understand why floaters tend to affect older patients, it is important to understand what the vitreous gel is and how it ages over time. The vitreous gel is 98% water and other molecules, mostly collagens and hyaluronan. These components form a “jelly-like” pattern that is amazingly clear. When we are born, the vitreous jelly has the consistency of a thick gel. Over time, in a process called liquefaction, the components that form the vitreous jelly break down. The vitreous jelly becomes less like a gel and more liquid in consistency. The liquefaction process doesn’t only affect the consistency of the vitreous jelly. It also alters the interactions within the vitreous, which can result in eye floaters and other retinal concerns.
What is a posterior vitreous detachment or PVD?
In particular, the gradual breakdown of the vitreous gel through liquefaction can cause a posterior vitreous detachment or PVD. This is because the vitreous gel has a very close relationship and a delicate attachment to the adjacent retinal tissue. With enough time and aging, the vitreous breaks down enough to cause a PVD, which occurs when the back edge of the vitreous jelly separates naturally from the retina. When this occurs, the patient often becomes very symptomatic and notes a worsening of floaters and occasionally flashing lights. Nearsightedness, or myopia, is a risk factor for a PVD at an earlier age than expected. A PVD can sometimes be a harbinger of a serious eye complication called a retinal tear or retinal detachment. Read more about the sudden onset of eye floaters here.
I have diabetic retinopathy. Could my eye floaters be bleeding in my eye?
Other types of floaters can be due to bleeding (vitreous hemorrhage), inflammation (uveitis or lymphoma), calcium spheres (asteroid), and sometimes even injected medications for macular degeneration.
In other words, floaters are more than a mere annoyance, like flying flies. They can be a warning sign of a PVD or other serious retinal injuries. If you notice a floater, it is important to be seen by a retinal specialist who can check on the health of your retina and continue to observe your retinal health over time. Read more about eye floaters at the American Academy of Ophthalmology.