Seeing sudden flashes of light at the edge of your vision can be unsettling, especially when they appear out of nowhere. For many people, these flashes are harmless and linked to normal age-related changes inside the eye. In some cases, though, they can be an early warning sign of a retinal problem that needs prompt attention.
The key is knowing the difference. This guide explains what causes flashes of light in your peripheral vision, what they typically look like, and, most importantly, when a flash is a reason to seek urgent care.
What Are Flashes of Light in the Eye?
Flashes of light, also known as photopsia, are brief bursts, streaks, arcs or sparkles that appear in your vision without an external light source. People often notice them in peripheral vision rather than directly ahead.
Flashes can occur when the retina, the light-sensitive layer at the back of the eye, is stimulated. This can happen when the vitreous, the gel-like substance inside the eye, pulls or tugs on the retina. The brain interprets this mechanical stimulation as a flash of light, even though no actual light is present.
Flashes are different from floaters, although the two can occur together. Floaters appear as small dots, shapes, lines or cobweb-like strands that move across your field of vision, while flashes are sudden bursts or streaks of light. New flashes, especially when accompanied by a sudden increase in floaters or a dark curtain or shadow across your vision, should be assessed promptly, as they can signal a retinal tear or detachment.
What Do Eye Flashes Look Like?
Eye flashes vary from person to person, but they are commonly described as:
- A quick streak or arc of light, often to one side
- A camera-flash-like burst that comes and goes
- Flickering, shimmering or sparkling lights
- Lightning-streak shapes at the edge of vision
These flashes are often more noticeable in dim lighting or when you move your eyes quickly. They may last a split second or flicker repeatedly over a period of time. Understanding what your flashes look like and how often they happen gives your ophthalmologist useful information when determining the cause.
Who Is More at Risk of Flashes?
Anyone can experience flashes of light, but certain factors can increase the likelihood of the eye changes that cause them, including posterior vitreous detachment and retinal tears. Knowing your risk factors can help you recognise when new flashes may need prompt assessment.
Factors that can increase the risk include:
Age over 50: Age-related changes can cause the vitreous gel to shrink and separate from the retina.
Short-sightedness (myopia): Particularly high myopia, which is associated with a higher risk of retinal problems.
Previous retinal tear or detachment: Having had a retinal tear or detachment in either eye increases the risk of another retinal problem.
Family history: A family history of retinal detachment can increase your risk.
Previous eye surgery: Particularly cataract surgery.
Eye or head trauma: A significant injury to the eye or head can increase the risk of retinal problems.
Having one or more of these risk factors does not mean you will develop a retinal problem. However, if you are at increased risk and notice new flashes, prompt eye assessment is important rather than waiting to see whether the symptoms settle.
What Causes Flashing Light in the Eyes?
Flashes of light are usually related to changes within the eye, particularly involving the vitreous gel and retina. Some causes are a normal part of ageing, while others require urgent assessment.
Posterior Vitreous Detachment (PVD)
A posterior vitreous detachment is one of the most common causes of flashes. The vitreous is the clear, gel-like substance that fills the inside of the eye. As we age, it naturally becomes more liquid and can pull away from the retina. This movement can stimulate the retina and create flashes of light, often accompanied by a sudden increase in floaters.
PVD becomes increasingly common with age and is often harmless. However, because the symptoms can resemble those of a retinal tear or detachment, an eye-care professional should assess new flashes.
Retinal Tear or Retinal Detachment
In some cases, the vitreous can pull strongly enough on the retina to cause a tear. A retinal tear can then develop into a retinal detachment, where the retina separates from the back of the eye. This is a serious, sight-threatening condition that requires urgent treatment.
Flashes associated with a retinal tear or detachment may occur alongside a sudden increase in floaters, blurred or reduced vision, or a dark shadow or curtain across part of your vision. These symptoms require urgent eye assessment.
Migraine With Aura
Not all visual flashes originate from the eye. Migraine with aura can cause shimmering lights, zig-zag patterns or other visual disturbances, often affecting both eyes. These symptoms typically develop gradually and last between 5 and 60 minutes, and they may occur with or without a headache.
Migraine-related visual symptoms tend to follow a different pattern from flashes caused by changes to the retina. However, new or unusual visual symptoms should still be assessed, particularly if you have not experienced them before.
Other Causes
Less commonly, flashes can be associated with inflammation inside the eye, eye trauma or other conditions affecting the retina. As flashes can have causes ranging from benign to sight-threatening, an eye examination is the most reliable way to determine what is causing them.
Are Flashing Lights in the Eyes Serious?
Flashing lights can be harmless, but they can also be an early sign of a retinal tear or detachment, so new or sudden flashes should not be ignored. The challenge is that a posterior vitreous detachment and a sight-threatening retinal tear or detachment can initially cause very similar symptoms.
This is why new flashes warrant prompt assessment by an eye-care professional. A dilated eye examination allows the retina to be examined for signs of a tear or detachment. If a retinal tear is identified, early treatment can help prevent it from progressing to a retinal detachment and reduce the risk of serious vision loss.
When Should You See a Doctor About Eye Flashes?
You should have an eye examination if you notice new flashes of light, particularly if they appear suddenly or are accompanied by other changes in your vision. Some symptoms can indicate a retinal tear or detachment and require urgent assessment.
Seek urgent eye care if you experience:
- A sudden onset of flashes, particularly if they are frequent or persistent
- A sudden increase in floaters or a shower of new floaters
- A dark shadow, curtain or veil across part of your vision
- A loss or reduction of peripheral or central vision
- Flashes following an eye injury
These symptoms can occur with a retinal tear or detachment, which can threaten vision if not treated promptly. If you develop these symptoms, seek urgent assessment from an ophthalmologist or eye-care professional. If urgent eye assessment is not readily available, attend your nearest emergency department.
How Flashes of Light Are Assessed
As flashes can be caused by changes to the vitreous or retina, a standard vision test alone may not be enough to identify the cause. Assessment may include dilating the pupils so the retina and vitreous can be examined in detail.
At Vision Clinic Sydney, Dr Kumar will ask about your symptoms and medical history and examine the back of the eye for signs of a retinal tear, retinal detachment or other possible causes. If a retinal tear or detachment is identified, appropriate treatment or referral can be arranged. If the examination shows a vitreous change without a retinal tear or detachment, you can be advised about what to expect and which symptoms should prompt further assessment.
Flashes of Light Versus Peripheral Vision Loss
Flashes of light are different from peripheral vision loss, although the two can sometimes be confused. Flashes are a visual symptom in which you see light or patterns that are not caused by an external light source, whereas peripheral vision loss means that part of your field of vision is missing or reduced.
The causes and urgency can also differ. If you are experiencing a loss or narrowing of your peripheral vision rather than flashes, our guide to peripheral vision loss explains some possible causes and when to seek assessment. If you are experiencing new flashes, particularly alongside new floaters or a shadow across your vision, seek prompt eye assessment.
Choose Vision Clinic Sydney for Your Eye Assessment
If you are experiencing new flashes of light, a prompt eye examination is the safest next step. To request an appointment or if you have an enquiry, please contact us via the following ways:
Call or message us: +612 9222 9188
Email us: reception@visionclinicsydney.com.au
Book online via our website
FAQs
What does it mean if you see flashing lights in your peripheral vision?
Flashing lights in your peripheral vision can occur when the vitreous gel inside the eye pulls or tugs on the retina. This commonly happens with a posterior vitreous detachment (PVD), which becomes more common with age and is often harmless. However, similar symptoms can occur with a retinal tear or detachment, so new flashes should be assessed promptly to rule out a more serious cause.
When should I worry about eye flashes?
Seek urgent eye care if flashes appear suddenly, particularly if they are accompanied by a sudden increase in floaters, a shower of new floaters, a dark shadow or curtain across your vision, or a loss of vision. These symptoms can indicate a retinal tear or detachment and require urgent assessment.
How long do peripheral eye flashes last?
The duration depends on the cause. Flashes associated with a posterior vitreous detachment can come and go and may continue intermittently for weeks or longer as the vitreous settles. Visual symptoms associated with migraine aura are usually temporary and can last from several minutes up to an hour. Seek prompt evaluation for persistent or worsening flashes, especially if accompanied by new floaters or changes in vision.
Can eye flashes be caused by a migraine?
Yes, migraine with visual aura can cause shimmering or flickering lights, zig-zag patterns and other visual disturbances. Visual aura typically affects both sides of the visual field and develops gradually, rather than appearing as sudden flashes in one eye. New or unusual visual symptoms should still be assessed, particularly if you have not experienced them before.
Can flashes of light mean I have a retinal tear?
They can. A retinal tear can occur when the vitreous pulls strongly on the retina, causing sudden flashes and sometimes new floaters. A tear can progress to retinal detachment, so sudden new flashes, especially when accompanied by new floaters or a shadow across your vision, require urgent assessment.
Do flashes of light always mean something is wrong with the retina?
No, flashes can occur with normal age-related changes to the vitreous, including posterior vitreous detachment, and can also occur with migraine with visual aura. However, because retinal tears and detachments can cause similar symptoms, an eye examination is important when flashes are new or sudden.
