Flashes of light at the side of your eyes, medically termed photopsias, are visual sensations like brief streaks, lightning-like flashes, or sparkling spots. These occur internally within the eye or brain, not from external light sources. While often benign, they can signal a more serious underlying eye condition requiring prompt medical attention. Understanding their potential causes is important for eye health.
Common Ophthalmic Causes
A frequent cause of flashing lights is posterior vitreous detachment (PVD), a common age-related process. The vitreous, a gel-like substance filling the eye, naturally liquefies and shrinks over time. As it shrinks, it pulls away from the retina, the light-sensitive tissue lining the back of the eye. This pulling on the retina creates mechanical stimulation, which the brain interprets as flashes of light, often seen in the peripheral vision. PVD itself is typically not painful and usually does not cause vision loss.
A more serious, though less common, cause of flashes is a retinal tear or detachment. If the vitreous gel pulls too strongly on the retina during PVD, it can create a tear. Fluid can then pass through this tear, lifting the retina away from its normal position, leading to a retinal detachment. These are serious conditions that can cause significant vision loss if not addressed quickly. Flashes are often described as lightning streaks or camera flashes and may be accompanied by a sudden increase in floaters.
Another distinct cause is ocular migraine, sometimes called retinal migraine or migraine with aura. Unlike flashes from retinal issues, ocular migraines are neurological events that can cause visual disturbances in one or both eyes. These visual symptoms may include shimmering lights, zigzag patterns, or blind spots, lasting typically from 5 to 60 minutes. Ocular migraines are due to temporary blood flow issues or nerve disruptions, often without a headache, and differ from the lightning-like flashes of retinal pulling.
Less common ophthalmic causes include direct eye trauma, where pressure on the retina can result in seeing flashes or “stars.” Certain inflammatory conditions within the eye or other rare disorders can also lead to the perception of light flashes.
When to Seek Prompt Medical Attention
While occasional flashes can be harmless, certain changes in their appearance or accompanying symptoms warrant immediate medical evaluation. Seek prompt medical attention if there is a sudden onset of new flashes, particularly if they are frequent or intense. A significant increase in the number or density of floaters, especially if they appear like a “shower” of spots, alongside flashes, is a concerning sign.
Any new shadow or a curtain-like effect appearing in your peripheral or central vision requires urgent assessment, as this can indicate a retinal detachment. Vision loss, whether partial or complete, or a narrowing of the visual field, are also warning signs. If flashes occur following any head or eye trauma, a medical professional should be consulted without delay. A comprehensive eye exam is important to rule out serious conditions and preserve vision.
How Causes Are Diagnosed
Diagnosing the cause of flashing lights involves a thorough eye examination by an ophthalmologist or optometrist. The process begins with an assessment of visual acuity and eye pressure. A comprehensive eye exam is then performed, including a dilated fundus exam.
During this exam, eye drops widen the pupils, allowing the doctor a clear view of the retina and vitreous gel at the back of the eye. This allows for detailed inspection for signs of vitreous detachment, retinal tears, or retinal detachment. If the view is obstructed or further clarification is needed, ancillary tests like optical coherence tomography (OCT) or ocular ultrasound may be used. These imaging techniques provide detailed cross-sectional images of the retina and vitreous, aiding in a precise diagnosis.
Treatments and Management
Treatment for flashing lights depends on the underlying cause identified during diagnosis.
Posterior Vitreous Detachment (PVD)
For posterior vitreous detachment (PVD) without complications, often no specific treatment is needed. The flashes and floaters associated with PVD typically become less noticeable over several weeks or months as the brain learns to ignore them. Monitoring is advised, and follow-up exams are recommended to ensure no complications like retinal tears develop.
Retinal Tears
If a retinal tear is detected, intervention is usually performed to prevent it from progressing to a retinal detachment. Laser photocoagulation is a common outpatient procedure where a laser creates small burns around the tear, forming scar tissue that seals the retina. Alternatively, cryotherapy, using a freezing probe, achieves a similar sealing effect.
Retinal Detachment
For a full retinal detachment, surgical repair is necessary to reattach the retina and prevent permanent vision loss. Surgical options include vitrectomy, where the vitreous gel is removed, or scleral buckling, which involves placing a band around the eye to gently push the eye wall inward. A gas or oil bubble might be injected to help hold the retina in place.
Ocular Migraines
Ocular migraines are generally managed by avoiding known triggers such as stress, dehydration, or certain foods. Pain relievers address associated headaches, and preventive medications may be prescribed for frequent occurrences.