Understanding Flashers and Floaters

Our eyes are filled with a jelly-like material called the vitreous. Throughout much of our life, the vitreous remains attached to the retina, which is the nerve tissue that lines the back wall of our eye. As we age, the vitreous can start to pull away from the retina. This is called a posterior vitreous detachment.

Floaters are caused by clumps of gel that start to form in the eye as the gel condenses during a posterior vitreous detachment. You may perceive them as ‘spots’ or ‘strands’ in your vision. Flashes of light are caused by the vitreous tugging on the retina as the gel continues to peel away.

Besides aging, flashes and floaters are also associated with nearsightedness and injuries to the eye


Most of the time, a posterior vitreous detachment will not cause any problems, and simple reassurance is all that is needed. The flashes eventually go away, and the floaters diminish and become less bothersome with time.

However, about 10% of people with a posterior vitreous detachment can develop a tear of the retina. Retinal tears are treated by sealing the edges with laser surgery, or by using a freezing technique (cryotherapy).

If left untreated, retinal tears can lead to a retinal detachment, which is separation of the retina from the back wall of the eye. A retinal detachment is a serious sight-threatening condition requiring a major surgical procedure to repair. It is important to diagnose and treat retinal tears before they become a retinal detachment.

What To Expect During Your Visit

Anyone who experiences a new onset of flashes or floaters should be examined within a day of their onset to make sure there are no serious problems with their eye.

An evaluation for flashes and floaters will typically last about one hour from the time you enter the exam room. You will be given eye drops that will dilate your pupils. These drops take about 15-20 minutes to work. They may make your eyes light sensitive and difficult to focus, especially up close, for several hours.

Your doctor will then shine several lights into your eyes, using both an eye microscope and ophthalmoscope. Specialized examination techniques will also be used to obtain a complete view of your retina. Scleral depression (where gentle pressure is placed on your eyelids while the eyes are examined) and a mirrored contact lens are additional ways to help diagnose any tears in your retina.

At the completion of your visit, your doctor will review the results of your evaluation with you.