Floaters & Flashes
Definition
Floaters and flashes are common visual phenomena that often occur as part of the eye’s natural aging process. While they are usually harmless, they can sometimes signal a serious retinal problem such as a retinal tear or retinal detachment.
What Are Floaters?
Floaters are small dark shapes that drift across your field of vision. They may appear as:
- Spots
- Dots
- Threads
- Squiggly lines
- Cobwebs
These shapes are actually tiny clumps of collagen, gel, or cells floating within the vitreous (the gel-like substance that fills the eye) and casting shadows on the retina.
What Are Flashes?
Flashes are brief streaks or bursts of light that may look like:
- Lightning streaks
- Camera flashes
- Sparkles
- “Stars” in your vision
They occur when the vitreous pulls, rubs, or tugs on the retina, stimulating the retina and creating the sensation of light.
Causes and Risk Factors
Causes of Floaters
Most floaters result from normal aging changes within the vitreous gel. As people age, the vitreous becomes more liquid and collagen fibers clump together, creating visible floaters.
Other causes include:
- Posterior vitreous detachment (PVD)
- Eye injury or trauma
- Eye inflammation (uveitis)
- Bleeding inside the eye
- Retinal tears or retinal detachment
- Eye infections
Causes of Flashes
Flashes most commonly occur when the vitreous pulls on the retina as it shrinks with age.
Other causes include:
- Posterior vitreous detachment (PVD)
- Retinal tears or retinal detachment
- Ocular migraines (may cause shimmering lights or zig-zag patterns)
Risk Factors
People are more likely to develop floaters and flashes if they:
- Are over age 50
- Are nearsighted (myopic)
- Have diabetes
- Have had cataract surgery or other eye surgery
- Have experienced eye trauma
- Have a history of retinal disease
Symptoms
Floaters
Common symptoms include:
- Small dark spots floating across vision
- Cobweb-like strands or squiggly lines
- Objects that move when the eyes move
- Floaters that are more noticeable against bright backgrounds such as white paper or blue sky
Flashes
Common symptoms include:
- Brief streaks of light
- Sparkles or lightning-like flashes in peripheral vision
- Intermittent flashes lasting days, weeks, or months
When Floaters and Flashes Are an Emergency
Sudden changes may indicate a retinal tear or retinal detachment and require immediate evaluation.
Seek urgent eye care if you experience:
- A sudden increase in floaters
- New flashes of light
- A dark shadow or curtain over part of your vision
- Loss of side (peripheral) vision
- Sudden blurred or decreased vision
These symptoms may indicate a retinal tear or retinal detachment and should be considered a medical emergency.
Diagnosis
An eye doctor may perform:
Dilated Eye Examination
- The pupil is widened using eye drops to allow a detailed view of the retina and vitreous.
Retinal Evaluation
- The retina is examined for tears, holes, vitreous detachment, or retinal detachment.
Treatment
Most Floaters
Most floaters do not require treatment and gradually become less noticeable over time as the brain adapts and the floaters settle out of the central visual field.
Severe Floaters
In rare cases, surgery (vitrectomy) may be considered if floaters significantly interfere with vision. Because surgery carries risks, it is generally reserved for severe cases.
Flashes
Treatment depends on the underlying cause:
- Age-related vitreous changes often require observation only.
- Retinal tears may require laser treatment or cryotherapy.
- Retinal detachment usually requires surgery.
Prevention
Not all floaters and flashes can be prevented, but the risk of complications can be reduced by:
- Having routine comprehensive eye exams, especially after age 50
- Managing diabetes and other systemic conditions
- Protecting the eyes from injury
- Seeking immediate evaluation for sudden visual changes
Summary
Floaters are small spots, threads, or cobweb-like shapes that drift across vision, while flashes are brief streaks or bursts of light caused by traction on the retina. Most floaters and flashes are related to normal aging and are harmless. However, a sudden increase in floaters, new flashes, a curtain-like shadow, or loss of vision may indicate a retinal tear or retinal detachment and requires urgent medical attention.