Seeing lights or flashes in one’s eyes is a common visual phenomenon that can range from a harmless, temporary occurrence to a signal of a more significant underlying condition. While many instances are benign, some situations warrant prompt medical attention to preserve vision.
Understanding Different Visual Sensations
People report various visual sensations when they see lights in their eyes, each with distinct characteristics. Flashes often appear as brief streaks, lightning-like bolts, or bright spots, sometimes resembling camera flashes in the peripheral vision. They can occur intermittently and are frequently more noticeable in dim lighting.
Another common sensation involves floaters, which are small specks, threads, or cobweb-like shapes that drift across the field of vision. They move with eye movement, seeming to dart away when one tries to look directly at them. Floaters are particularly visible against a plain, bright background, such as a white wall or a clear blue sky. Other visual disturbances can include halos, appearing as rings of light around bright sources, or shimmering, which presents as distorted or zigzag lines, often associated with certain types of migraines.
Common Explanations for Seeing Lights
Many instances of seeing lights or floaters stem from natural changes within the eye, particularly the vitreous gel. This clear, jelly-like substance fills the majority of the eyeball. As individuals age, the vitreous undergoes a process called vitreous syneresis, where it liquefies and shrinks, forming small clumps or strands. These clumps cast shadows on the retina, the light-sensitive tissue at the back of the eye, which are perceived as floaters.
As the vitreous gel continues to change, it may pull away from the retina in a process known as posterior vitreous detachment (PVD). This detachment is a normal part of aging and can cause intermittent flashes of light as the vitreous tugs on the retina. Such flashes often appear like flickering lights or lightning streaks, especially in the peripheral vision. While PVD is often harmless, new onset flashes and floaters should be evaluated to ensure no complications are present.
Visual disturbances can also arise from ocular migraines. These migraines can cause temporary visual phenomena, such as shimmering zigzags, flickering lights, or blind spots, that may spread across the visual field and typically resolve within about 20 minutes. Additionally, mechanical stimulation, such as rubbing the eyes, can produce brief flashes of light called phosphenes.
Concerning Causes and Warning Signs
Serious eye conditions can also cause visual disturbances and require immediate medical attention. A retinal tear or detachment is a serious condition where the retina separates from the back of the eye. Symptoms often include a sudden increase in new floaters, which may appear like a shower of black spots, and flashes of light, described as lightning streaks. An important warning sign is the appearance of a dark shadow or a “curtain” moving across or blocking part of the field of vision.
Vitreous hemorrhage, which is bleeding into the vitreous gel, can also cause sudden visual changes. This condition may present with blurred vision, an abrupt increase in floaters, or flashes of light. The severity of vision impairment depends on the amount of blood. Causes can include diabetic retinopathy, eye injuries, or the vitreous pulling on a retinal vessel.
Inflammation of the optic nerve, known as optic neuritis, can lead to vision loss and sometimes the perception of flashing or flickering lights. This condition causes a sudden decrease in vision, often accompanied by eye pain that worsens with movement. New, sudden, and persistent visual changes, especially when accompanied by other neurological symptoms like weakness or speech difficulty, might indicate a stroke or transient ischemic attack (TIA).
What to Expect at the Eye Doctor
If you experience new or significantly increased flashes or floaters, or any vision changes like a shadow or curtain, consult an eye care professional promptly. An optometrist or ophthalmologist will perform a comprehensive eye examination. This often includes a dilated eye exam, where eye drops are used to widen your pupils, allowing the doctor to thoroughly inspect the retina and vitreous.
Additional diagnostic tools like ocular ultrasound or optical coherence tomography (OCT) may be used to gain a more detailed view of the retina. For benign conditions like PVD, reassurance and monitoring are the primary approach, as symptoms often become less noticeable over time.
If a serious condition like a retinal tear or detachment is diagnosed, timely intervention is important for preserving vision. Retinal tears can often be treated with in-office procedures such as laser photocoagulation or cryotherapy to seal the tear and prevent fluid from leaking. More extensive retinal detachments may require surgical procedures like scleral buckling or vitrectomy to reattach the retina.