The three most common explanations for seeing flashes of light include:
1. An ocular migraine.
2. A problem with the retina such as a tear or detachment.
3. A separation of the jelly-like fluid away from the retina called a Vitreous Detachment.
Most ocular migraines involve seeing a shimmering pattern from both eyes. This will last from 10 minutes to 30 minutes and then resolve.
With a retinal tear, sparks of light will be seen and will persist for a long time along with the sudden appearance of “floaters” or little black specks in the vision. Patients sometimes describe this as seeing a gnat or a spider web. It can be a line or a dot. Retinal tears are serious. They should be diagnosed and treated immediately to prevent a retinal detachment.
In the majority of cases, however, a person experiencing flashes of light has a condition that is not dangerous called Posterior Vitreous Detachment. In this, the jelly-like fluid in the back of the eye separates from the retina. This leads to a retinal tear in less than 2 percent of cases. Most flashing will stop, and floaters will diminish slowly.
The only way to know which condition applies to you is to have an exam with an eye specialist immediately.