Flashes and floaters

 

Are floaters in the vision something to worry about?

 

The eye is like a camera with the lenses at the front and the photographic film (retina) at the back and between the two in the “body” of the camera is a clear jelly called vitreous. The jelly is not of uniform consistency and usually even young and healthy people have smaller clumps of jelly floating around.

These small floaters are normal and usually are seen when you look at a plain surface such as a white wall or when looking at a clear blue sky.  With the passage of time however most of the jelly starts to degenerate and turn to a more watery consistency. Eventually the remaining jelly that is up against the retina or photographic film at the back of the eye suddenly pulls away and collapses down into smaller lumps of jelly. This is called a “posterior vitreous detachment or separation”. It usually produces a sudden shower of new floaters and sometimes is associated with flashing light sensations. In most people the jelly “lets go” of the retina as it pulls away and does not cause any problems and the floaters usually improve with the passage of time.

In a small number of people there is abnormal adhesion between the jelly and retina in places and as the jelly pulls away it does not want to “let go” of the retina and pulls on the retina hard enough to tear it away from the back wall of the eye. This usually produces a more pronounced shower of new floaters and is often associated with flashing light sensations. If you push on your eye accidently with a finger through the eyelid it creates a flashing light sensation which is due to mechanical stimulation to the retina with the pushing force of the finger. The flashing lights produced as the jelly pulls on the retina is created in a similar way but this time it is pulling from the inside rather than pushing from the outside.

 

Anyone with sudden onset of flashing lights associated with a new shower of floaters must be assumed to have a retinal tear until proved otherwise and needs to be seen by an eye doctor with a degree of urgency.  A tear in the retina is easily treated with laser as an out-patient procedure but if left and the retinal tear develops into a retinal detachment it requires a formal operation in theatre.

A small number of patients are very troubled by their floaters.  Patients who are short sighted (myopic) can in particular have difficulty with excessive floaters but they can affect all types of patient.  If you develop a sudden appearance of significant floaters you first need to have an urgent eye check to exclude a retinal tear.  If no tear is seen but the floaters are very troublesome I would suggest waiting at least 6 months to see if the symptoms improve (the floaters can "float" to the bottom of the main eye cavity with gravity and out of your vision or the brain learns to ignore them).  

If after 6 months you are still troubled then surgery may be indicated.  Laser treatment for floaters is relatively ineffective and treatment is by removing the jelly that contains the floaters that occupies the main eye cavity.  This operation is called a vitrectomy and is usually very sucessful in treating the floaters.  The surgery can be performed as a day case procedure under local or general anaesthetic.