Flashes and Floaters

What are Flashes and Floaters?

Floaters are a common symptom and although they can be normal, they often need to be acutely evaluated. If floaters come on suddenly and are new, a dilated eye exam is needed to make sure they are not a symptom of a more serious condition such as a retinal tear or vitreous hemorrhage.

What is actually seen when “floaters” are reported is the shadow of a condensation of proteins/collagens floating in the vitreous of the eye. Some people will notice these benign shadows for most of their life, although they can become more pronounced or numerous with age. Because floaters are the shadow from material in the vitreous, this symptom will be noted when anything is present in the eye to cause shadow formation on the retina.

Vitreous hemorrhage can occur for a number of reasons. This is the leaking of blood into the vitreous. Blood in the vitreous can cause anything from mild floaters to nearly complete loss of vision depending on the amount of blood. If this does not self-resolve, the vitreous can be removed to alleviate the symptoms.

The most common cause of an acute, notable floater in the central vision is what is known as a “posterior vitreous detachment” (PVD). This occurs in all eyes, but the timing and symptoms can vary greatly from person to person. This event occurs as the vitreous naturally liquefies and shrinks in size over time. As this happens, the vitreous pulls away from the surface of the retina, eventually detaching from the face of the optic nerve and releasing what is known as a “weiss ring.” This ring can cause an acute new floater and can typically be seen clinically with a dilated eye exam.

Flashing lights may be reported in conjunction with new floaters. The retina does not house any pain sensing nerve endings. When it comes to sensory input, the retina specializes in light. This means if the retina is pulled on, torn, or pressed on, its only response is to send a flash of light to the brain. These flashes are white, and often peripheral. They are usually described as a lightning arc or camera flash off to the side of the field of vision.

Flashes need to be evaluated with a dilated eye exam as soon as possible. Although posterior vitreous detachments are often uneventful and uncomplicated, the process can occasionally result in a retinal tear that may progress to a detachment if left untreated. The earlier these complications are identified, the more successful and less invasive the treatment by a retina specialist may be.

Floaters which have been present for most of life, or gradually change in prevalence over time are not generally considered an emergency. However, new floaters of any kind, and new floater(s) associated with flashes of light need to be evaluated with a dilated eye exam as soon as possible. Posterior vitreous detachments – even in the absence of complications – need to be examined and monitored to help catch early tears and prevent more serious retinal detachments, etc.

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