Floaters 101

Doctor examining the eye for floaters. Credit: Eric Audra

Cobwebs, rings, spots and floaters are words used to describe annoying things that we sometimes see in our vision or visual field. Most of us have seen one or two in our lifetime and some of us may be bothered by them to a much greater extent. 

What Are Floaters?

Floaters are the common name given to things we see from time to time in our vision. Floaters usually arise from the vitreous humor, the gel-like substance the fills the cavity inside our eye.

The vitreous is firm and clear when we are young. However, as we age, the vitreous tends to change consistency and liquefy a bit. When this occurs, the gel may become opacified or develop strands or spots that actually float around inside the eye. These clumps of tissue tend to be more dense so light cannot shine through them very well. As a result, light enters the eye and the dense tissue casts a shadow onto the retina and we see it as a shadow or speck floating out in space.

Floaters can appear as the following:

  • specs
  • dots
  • threads or strands
  • rings
  • cobwebs

What Makes Floaters More Prominent?

Floaters are much more visible when looking at a computer screen or more commonly, looking at a bright blue sky. Professional painters often complain about seeing floaters because they are constantly looking at large white backgrounds.  

Floaters also tend to move. When you move your eye to focus on them, they tend to shift to a different spot very quickly.

They can drift and move around inside your eye but often it is just your eye movement that gives you the feeling that the floater is moving around.

Most of us tend to ignore floaters or just get used to them. Our brains are pretty smart about ignoring them. Most floaters tend to settle into the bottom part of our eyes due to gravity but sometimes, the right amount of light at the right angle can cause them to be more visible.

Are Floaters Harmful?

Most floaters are benign. However, sometimes a floater can be a sign of something much more dangerous. A sudden increase in floaters, an increase in the size of a floater or new flashing lights that accompany the floater can be a sign of a retinal tear or detachment. A retinal tear or detachment is a tear or separation of the retina, the delicate photosensitive nerve tissue that lines the back of the eyeball. In the eye care profession, a tear or detachment is considered an emergency. The success of the treatment of a tear or detachment depends upon the part of the retina that is involved and the length of time treatment is begun.

What Causes Floaters?

The most common cause of new floaters is the development of posterior vitreous detachment (PVD). In PVD, the vitreous may actually separate from the retina. Although a PVD can occur due to trauma, it most commonly occurs in people in their mid 50’s. Aging causes the vitreous to shrink and peel away from the retina. If the process occurs rapidly, it can tug on the retina, causing symptoms of flashing lights.

If it pulls away hard enough, a retinal tear can occur. Fluid may build up behind the retina, separating it from the wall of the eye.

Other causes of floaters can be diabetic eye disease, bleeding or hemorrhages in the vitreous, vitreous inflammation, eye injury and eye tumors. If you develop new floaters you should immediately see an eye doctor for a comprehensive examination. The doctor will examine the back of your eye by instilling special medicated eye drops into the eye that will enlarge the pupil.

Primary Care of the Posterior Segment, Third Edition, Alexander, Larry, McGraw-Hill Publishing, 2002.

Continue Reading