Many patients experience flashing lights when they experience significant head trauma. Flashing lights which are transient and well-connected to an immediate episode of head injury are usually of little consequence. Often individuals see stars in front of their eyes or strange visual patterns related to the traumatic episodes.
What if unusual visual phenomenon or hallucinations persist?
One important question an ophthalmologist can ask is if the visual symptoms are in one or both eyes. This seems simple but is often not. In general, many patients have difficulty in distinguishing what’s happening to the left or right side of their vision from their left or right eye.
Symptoms occurring in one eye only are usually associated with an intrinsic eye problem while symptoms occurring in both eyes are usually related to disturbance within the brain. Thus, a careful history taken by an experienced ophthalmologist is important in determining the source of the problem.
Flashing lights, especially when they are accompanied by dark spots (floaters), can sometimes indicate tears in the retina. Retinal tears can be caused by head, and especially ocular, trauma. Tears need to be detected early because they can lead to retinal detachment. Retinal tears can be treated with a simple laser intervention done in the ophthalmologist’s office if they are discovered early. Laser spots are used to surround the tear and effectively prevent retinal detachment. Any trauma patient experiencing persistent flashing lights after an automobile accident should be thoroughly checked by an ophthalmologist.
What if the lights are in both eyes, or colored, or have a pattern?
Attention must then turn to the brain. A visual field test should be performed to detect any abnormality in peripheral vision. Visual fields tests were discussed in detail in a previous blog. Individuals often experience zig zagging patterns of lights just before a migraine headache (a migraine aura). Head trauma can exacerbate migraine headaches in patients who previously only had such headaches on rare occasions.
I have personally examined many patients with increased frequency of migraine headaches after head trauma or whiplash. Such patients are often worried they are having a stroke. Headache syndromes are usually evaluated and treated by neurologists.
Sometimes patients continue to experience strange visual symptoms associated with flickering or lights weeks, or even months, after an accident. Such patients may require the reassurance of a normal MRI scan of the brain. These unusual visual symptoms can be quite disturbing but most commonly do not indicate brain injury unless accompanied by other neurologic problems.
The important message in this blog is to question patients about flashing lights, or any lights that seem abnormal. Such symptoms are common and indicate eye or brain abnormalities. It is extremely important not to miss early retinal detachment. Many patients can be reassured that the retina is ok, and lights by themselves usually do not indicate a stroke or brain injury.
