Floaters in the Eyes

By Michael J. Dodd, MD

A common complaint I hear from patients over age 50 is about “floaters.” In this article I will discuss the cause of these annoying symptoms and what, if anything can be done.

To understand the cause of floaters a little eye anatomy background is helpful. Behind the colored iris is the clear lens and behind the lens is a viscous, clear material called the vitreous humor, or vitreous for short. The purpose of the vitreous seems to be to help maintain the shape eye and keep it from collapsing. The vitreous is clear and allows natural light to pass unimpeded to the retina where the light information is transmitted to the brain for perception of images.

As we age the vitreous loses some of it gel-like consistency and may become more water-like and tend to painlessly collapse toward the center of the eye. When this happens, the peripheral part of the vitreous, which is attached at multiple microscopic points along the retina, may tug on the retina. This tugging or “traction” on the retina can stimulate the retina to send light impulses to the brain. Patients perceive this as “light flickers” or “flashes” in their side vision. Patients may sometimes see this flashing — known as photopsia — without a vitreous detachment. This can be caused by “ocular migraines” or rarely without any apparent cause. Sometimes the flashing from vitreous traction may occur in clusters and be quite disturbing. It can last for minutes or hours and rarely for days.

This vitreous traction will eventually stop when the vitreous attachment to the retina finally separates. Once the separation occurs, floaters may appear. They may have many shapes and sizes. Most patients describe them as “comma shaped,” or “C–shaped” or “rings,” which move back and forth, or up and down, with eye movement. Large floaters can drift in the central visual field and partially block vision, especially reading vision. So floaters are part of the normal anatomy of the eye, which have detached from their normal position. Therefore they are often referred to as “vitreous detachments.”

What can be done about these annoying floaters? Unfortunately, not much. They remain forever, but with time they usually break up into smaller, less noticeable fragments and become less noticeable. So a vitreous detachment is considered one of those normal aging events that affect many older people.

But our story does not end here. Rarely when the vitreous tugs on the retina, a break can occur in the retina and this may lead to a retinal detachment (RD). This must be diagnosed and treated quickly to avoid permanent vision loss. Also, some floaters can be caused by a hemorrhage into the vitreous from a leaky blood vessel in diabetic patients. This also needs to be evaluated and treated.

So any patient with a new symptom of floaters and light flashes needs to be evaluated soon to be certain there is no hemorrhage or RD. Consult with your eye specialist if these symptoms occur.

Dr. Dodd is a practicing ophthalmologist at Maryland Eye Associates located in Annapolis, Prince Frederick and Upper Marlboro, as well as an instructor at the University of Maryland Department of Ophthalmology. He can be reached at 410.224.4550 or [email protected]


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