A sudden flash at the edge of your vision can feel like a camera going off in a dark room. It may happen once, then disappear – or return as brief sparks, streaks or lightning-like arcs. Are flashing lights urgent? Sometimes they are, particularly when they are new, persistent or accompanied by other changes in your sight. A prompt eye assessment can rule out conditions that need treatment to protect your vision.
Flashes are often harmless, but they should not be ignored simply because they are painless. The most concerning causes can affect the retina, the light-sensitive tissue lining the back of the eye. Retinal problems may progress without discomfort, so the pattern of your symptoms matters.
When are flashing lights urgent?
New flashing lights should generally be assessed on the same day or as soon as possible, especially if they occur in one eye and are different from anything you have experienced before. Contact an optometrist for an urgent eye examination rather than waiting for your next routine check-up.
Seek immediate urgent care if flashes occur with a sudden shower of floaters – small dark dots, squiggles or cobweb-like shapes – or if you notice a shadow, grey patch or curtain moving across your vision. A reduction in side vision, blurred vision that does not clear, or a dark area in your field of view also needs urgent assessment.
It is particularly important to act quickly after an injury to the eye or head, such as being hit by a ball, falling, or a workplace accident. People with severe short-sightedness, previous eye surgery, a previous retinal tear or detachment, or a family history of retinal detachment may also have a higher risk of retinal concerns.
If you have a curtain over your vision, sudden significant loss of sight, or flashing lights after serious trauma, do not drive yourself. Arrange help getting to urgent care or an emergency department.
Why flashes can happen
Inside the eye is a clear, gel-like substance called the vitreous. As we get older, the vitreous naturally becomes more liquid and can pull away from the retina. This is called a posterior vitreous detachment, or PVD. It is common from middle age onwards and may cause flashes and new floaters.
A PVD often settles without treatment. However, as the vitreous separates, it can occasionally tug hard enough to create a retinal tear. Fluid may then pass through the tear and lift the retina away from the back of the eye, causing a retinal detachment. This is why a dilated retinal examination is needed for new flashes, even when the symptoms seem minor.
Retinal tears can often be treated before a detachment develops. Early assessment gives your eye care practitioner the best chance to identify a problem while treatment options are simpler and vision is less likely to be affected.
Flashes can also be associated with inflammation inside the eye, migraine, or less commonly other neurological conditions. The cause cannot be confirmed based on symptoms alone, which is why a thorough examination is worthwhile.
Flashes from migraine versus flashes from the eye
Visual migraine symptoms often look different from retinal flashes. They may appear as shimmering zigzags, flickering patterns, heat-wave distortion or expanding coloured shapes. These effects commonly affect both eyes, even though they may seem to sit on one side of your view, and typically build over several minutes before resolving within about 5 to 60 minutes.
Retinal flashes are more often brief white arcs or sparks at the outer edge of vision. They may be more noticeable in dim light, when moving your eyes, or when you wake during the night. They are usually felt in one eye.
There is overlap, so it is not always easy to tell the difference at home. If this is your first episode of visual disturbance, the pattern is unusual for you, or you are unsure whether it affects one or both eyes, arrange an assessment. Seek urgent medical help for visual symptoms with weakness, facial drooping, difficulty speaking, severe headache or confusion.
What happens at an urgent eye examination?
An urgent eye examination is designed to look beyond the front of the eye and check the retina carefully. Your optometrist will ask when the flashing started, whether it is in one or both eyes, and whether you have noticed floaters, a curtain, blurred vision or recent trauma.
Your vision and eye pressure may be checked, followed by a detailed look at the front and back of the eye. Dilating drops are often used to widen the pupil so the far edges of the retina can be examined properly. These drops can make your near vision blurry and increase light sensitivity for several hours, so bringing sunglasses and arranging transport can be helpful.
If there is a retinal tear, detachment or another concern that needs specialist treatment, your optometrist can organise an urgent referral to an ophthalmologist. If the examination shows a PVD without a tear, you may still be asked to monitor your symptoms and return for review. New or worsening floaters, flashes, or any curtain-like shadow should always be reported promptly, even after a reassuring first examination.
Do not wait for your next glasses check
It can be tempting to put flashes down to tired eyes, screen use or needing a new prescription. Screens can cause eye strain, dryness and temporary blur, but they do not usually cause sudden lightning-like flashes in one eye. A change in your glasses prescription also does not explain new flashes or a sudden burst of floaters.
This does not mean every flash signals a serious condition. Many people are diagnosed with a normal age-related vitreous change and simply need monitoring. The trade-off is clear: a same-day assessment may prove reassuring, while delaying assessment could miss a treatable retinal tear.
Children and younger adults can experience flashes too. While age-related vitreous changes are less common in younger people, flashes after an eye injury, during sport, or alongside new vision changes still deserve prompt advice. Parents should take reports of flashing, dark spots or a missing patch of vision seriously, particularly if a child has been hit near the eye.
What to do while waiting for care
Make a note of when the flashes began and whether the symptoms are changing. Cover one eye and then the other to see whether the effect is present in one eye or both, but do not let this home check delay care. Avoid driving if your vision is affected or if you are likely to have dilating drops at your appointment.
Do not rub or press on the eye, particularly after an injury. There is no safe home remedy for possible retinal symptoms, and resting your eyes will not treat a tear. If you wear contact lenses, you can remove them if the eye is irritated, but flashing lights still need professional assessment.
For patients in Auburn and surrounding Western Sydney, Boda Family Eye Care can assess urgent eye concerns and coordinate referral when specialist care is required. Let the team know when booking that you have new flashes, floaters, a shadow or reduced vision so your concern can be triaged appropriately.
Your eyesight is too valuable to gamble on a symptom that may be harmless but can occasionally signal something time-sensitive. If flashes are new, one-sided, increasing, or paired with floaters or a curtain in your vision, arrange urgent eye care today.