When Are Floaters and Flashes a Warning Sign?
Most people experience some floaters at some point, and an occasional floater that has been present and stable for a long time is usually not a cause for concern.
However, certain patterns of floaters and flashes warrant prompt assessment by an eye specialist, ideally within 24 to 48 hours, as they may indicate a retinal tear or detachment:
A sudden onset of new floaters, especially if numerous (a "shower" of floaters)
New or increased flashes of light, particularly in peripheral vision
A dark shadow or curtain appearing in your field of vision, often starting from one side
A sudden decrease in vision
Floaters that appear suddenly after an eye injury or recent eye surgery
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Learn more about Retina Detachment here
FLOATERS AND FLASHES: WHEN TO WORRY
What Are Eye Floaters?
Floaters are small specks, dots, threads, cobwebs, or squiggly lines that drift across your field of vision.
They are most noticeable when looking at a plain, bright background, such as a clear sky, a white wall, or a computer screen.
Floaters are caused by tiny clumps of collagen fibres or cells within the vitreous, the clear, gel-like substance that fills the inside of the eye between the lens and the retina.
These clumps cast shadows onto the retina, which the brain perceives as floating shapes.
What Are Flashes of Light?
Flashes are brief streaks, sparkles, or flickers of light, often described as similar to a camera flash or lightning. They typically occur when the vitreous gel tugs or pulls on the retina, stimulating it mechanically and causing the retina to send a signal that the brain interprets as light, even though no actual light is present.
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Flashes are most often noticed in dim lighting or in peripheral (side) vision.
Why Do Floaters and Flashes Happen?
The most common cause is a normal age-related process called posterior vitreous detachment (PVD). As we age, the vitreous gel gradually shrinks and becomes more liquid, eventually separating from the surface of the retina. This is extremely common, particularly after the age of 50, and on its own is not usually sight-threatening.
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However, the same process that causes a PVD can, in some cases, also cause a retinal tear. If the vitreous gel is firmly attached to a weak area of the retina, the traction during separation can tear the retinal tissue.
A retinal tear can, in turn, lead to fluid passing through the tear and lifting the retina away from the underlying tissue, a retinal detachment, which requires urgent treatment.
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​Other causes of floaters and flashes include:
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High myopia (short-sightedness), which increases the risk of retinal tears and PVD related complications.
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Previous eye surgery, including cataract surgery
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Eye trauma or injury.
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Inflammation inside the eye (uveitis).
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Bleeding within the vitreous (vitreous haemorrhage), which can occur in diabetic eye disease or retinal vein occlusion
How Are Floaters and Flashes Assessed?
Assessment typically involves a dilated fundus examination, where eye drops are used to widen the pupil, allowing the retina to be examined carefully for any tears, areas of thinning (such as lattice degeneration), or early signs of detachment. Additional imaging, such as retinal photography or ocular ultrasound (particularly if there is bleeding obscuring the view), may also be used.
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If a retinal tear is found, it can often be treated promptly with laser photocoagulation or cryotherapy, sealing the tear before it progresses to a full retinal detachment. If a retinal detachment has already occurred, surgical treatment is required.
Are Floaters Themselves Treatable?
For most people, floaters caused by a benign PVD do not require treatment. Over time, many people find that floaters become less noticeable as the floaters drift out of focus and the brain adapts, though they do not typically disappear completely.​ For floaters that are dense, persistent, and significantly affecting vision or quality of life, two treatment options exist:
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YAG laser vitreolysis uses a laser to break up large, well-defined floaters into smaller fragments that are less noticeable. We are cautious about recommending it as results tend to be inconsistent, with only partial improvement in the majority of cases and complete resolution of floaters being uncommon. It is ineffective for diffuse or multiple fine floaters that trouble most patients, particularly in myopic eyes and also carries genuine risks, including cataract from inadvertent lens injury, raised eye pressure, inflammation, and, rarely, retinal tears or detachment.
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Vitrectomy is a surgical procedure that removes the vitreous gel, along with the floaters within it, and replaces it with a clear saline solution. It is the most definitive treatment for floaters but carries the risks associated with any intraocular surgery, including retinal tear, retinal detachment, cataract formation, and infection. Surgery is not recommended simply because floaters are visible.
The decision depends on how significantly they affect daily function: reading, driving, screen work, and overall quality of life. A small number continue to experience persistent, disabling symptoms despite a reasonable period of observation and can be considered for vitrectomy. As with any surgery, the decision involves weighing the severity of symptoms against the risks of the procedure.
Common Myths About Floaters
Myth 1: Everyone gets used to floaters
Not always. Many patients do adapt over weeks to months, but a meaningful minority continue to notice their floaters indefinitely, particularly against bright or plain backgrounds.
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Myth 2: Floaters disappear
Some become less noticeable over time as they settle within the vitreous or as the brain adapts. Others remain essentially unchanged. It is inaccurate to promise that floaters will resolve on their own.
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Myth 3: Eye drops can dissolve floaters
There is no convincing clinical evidence that any topical eye drop dissolves or reduces vitreous floaters. Patients should be cautious of products marketed with this claim.
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Myth 4: Certain foods, such as pineapple, cure floaters
This claim circulates widely online but is not supported by clinical evidence. There is no dietary intervention currently shown to resolve vitreous floaters. It is worth addressing directly, since patients often ask about it in consultation
Five Take Home Messages
1. Floaters are common and usually harmless, but a sudden increase deserves an eye examination.
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2. Surgery is based on functional impact, not the mere presence of floaters.
3. No eye drop or food is proven to dissolve floaters.
4. Flashes of light or a curtain-like shadow alongside floaters need urgent assessment.
5. Most sudden floaters are a normal posterior vitreous detachment (PVD), not a retinal detachment, but only an examination can tell the difference.​​
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Seeing a Retina Specialist for Flashes and Floaters
New flashes or floaters can sometimes be caused by changes in the vitreous , but they may also be an early sign of a retina tear or retina detachment. A retina examination is therefore important when symptoms are new or suddenly worsening.
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Dr Paul Zhao is a fellowship-trained vitreoretinal surgeon and retina specialist in Singapore who evaluates and treats retina tears, retina detachment, vitreous haemorrhage and symptomatic floaters. He can determine whether your symptoms are related to posterior vitreous detachment or another retina condition and whether observation, laser treatment or vitreoretinal surgery is appropriate.
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Frequently Asked Questions
