Experiencing white flashes in your vision can be a disquieting sensation. These flashes appear as brief streaks or bursts of light not caused by external sources. They can range from harmless occurrences to symptoms of serious underlying conditions.
Flashes Originating in the Eye
Many flashes stem from changes within the eye, particularly involving the vitreous gel. This clear, gel-like substance fills the space between the lens and the retina. With aging, the vitreous gel can begin to shrink and liquefy.
This age-related change can lead to posterior vitreous detachment (PVD). During PVD, the shrinking vitreous gel separates from the retina, the light-sensitive tissue at the back of the eye. As the vitreous pulls away, it can tug on the retina, causing flashes described as lightning streaks or camera flashes, often noticeable in peripheral vision or darker environments. PVD is common, affecting over half of individuals by age 70, and while not vision-threatening, it warrants examination to rule out complications.
A more serious cause of flashes is a retinal tear or detachment. If the vitreous gel pulls too strongly, it can create a tear in the retina. Fluid can then pass through this tear, lifting the retina away from its supporting layers, leading to a retinal detachment. Flashes associated with these conditions may be sudden, more constant, and are often accompanied by a sudden increase in floaters (specks or cobwebs) or a darkening shadow or “curtain” in the field of vision. Eye trauma or inflammation can also induce flashes by physically affecting the retina.
Flashes with Other Causes
Not all visual flashes originate within the eye; some can be symptoms of systemic or neurological conditions. One common non-ocular cause is migraine aura, which affects about 20-40% of people who experience migraines. These visual disturbances can precede or accompany a migraine headache, or sometimes occur without a headache, sometimes called an “ocular” or “retinal” migraine. Visual aura can manifest as:
- Flashes of light
- Shimmering spots
- Zigzag patterns
- Temporary blind spots
These affect both eyes and last between 5 and 60 minutes.
Another cause can be orthostatic hypotension, which involves a sudden drop in blood pressure, such as when standing up quickly. This temporary reduction in blood flow to the brain and eyes can cause transient flashes or a sensation of “seeing stars.” Certain medications may also list visual disturbances, including flashes, as a side effect. These instances are temporary and resolve once the underlying cause is addressed or the medication is adjusted. Flashes can also indicate more serious neurological conditions, though these are less common than ocular or migraine-related causes.
When to Seek Urgent Medical Care
Seek prompt medical attention if you experience certain warning signs alongside flashes. A sudden onset of new flashes, particularly if accompanied by a new shower of floaters (small specks or cobwebs), requires immediate evaluation by an eye care professional. This combination of symptoms can indicate a retinal tear or detachment, which requires urgent intervention to preserve vision.
The appearance of a dark “curtain” or shadow progressing across your field of vision indicates retinal detachment. Any flashes occurring after a head injury or direct eye trauma should also prompt an immediate medical visit. Any sudden decrease or loss of vision, or persistent flashes that worsen or do not resolve, should be evaluated without delay. Even if flashes seem minor, a professional eye examination is recommended to rule out potentially serious conditions.
Medical Evaluation and Management
When you seek medical attention for visual flashes, an ophthalmologist will conduct a comprehensive eye examination. This includes a visual acuity test to assess your sharpness of vision and a dilated eye exam. During a dilated exam, eye drops widen your pupils, allowing the doctor to get a clear view of the retina and the vitreous gel at the back of your eye. If the view is obstructed or more detail is needed, imaging tests such as optical coherence tomography (OCT) or ocular ultrasound may be performed.
A thorough examination is needed to determine the cause of the flashes. Management depends entirely on the underlying diagnosis. For instance, if posterior vitreous detachment is diagnosed without complications, often no specific treatment is needed, and symptoms may become less noticeable over time. However, if a retinal tear is identified, procedures like laser photocoagulation or cryotherapy may be performed to seal the tear and prevent progression to detachment. These in-office procedures create small scars that help secure the retina.
In cases of retinal detachment, surgical intervention is necessary, which may include vitrectomy, scleral buckling, or pneumatic retinopexy. These procedures aim to reattach the retina to the back of the eye. For migraine-related flashes, management focuses on identifying and avoiding triggers, and medication may be prescribed to prevent or treat migraine attacks. For other causes, such as medication side effects or blood pressure issues, addressing the root problem resolves the flashes. Many causes of flashes are benign, but early detection through a comprehensive eye examination helps preserve vision, especially for more serious conditions.