We always tell patients to call us immediately if they notice "flashing lights" or "floating spots" suddenly in your vision. Our primary concern is a tugging on the retina that could lead to a retinal detachment. The retina is a very thin transparent tissue supplied by blood vessels. In front of the retina is a clear fluid called the vitreous. It has an outer layer that keeps the fluid contained and is connected to the retina in a few key spots. Over time, and especially in nearsighted people, the fluid can move and tug on the retina. When this occurs, there could possibly be a retinal detachment which can be vision threatening. If you think you may have a retinal detachment, call us immediately.
On the other hand, other flashing lights can occur. One of the most common occurs in patients with a migraine history and in fact, recently happened to me! This flash is called an ophthalmic migraine and typically comes on suddenly. In my case I was working on the computer and suddenly noticed that my straight-ahead vision was blurry. Over the next few minutes the blur became a shimmering, jagged light which gradually moved from the central part of my vision toward the outside part of my vision. You can see in the attached drawings I made while the event was going on exactly what it appeared like to me at certain times of this progression. Typically after 15-30 minutes, the zigzag lines go away. Most of the time these ophthalmic migraines do not result in any side vision loss or headache. The patient may report mild tiredness after. Ophthalmic migraines are innocuous in that they do not suggest any other neurologic condition.
So, flashing lights are a concern. We want to make sure you don't have a retinal detachment. But all flashing lights do not mean retinal problems. If you have ophthalmic migraine questions don't hesitate to e-mail me so we can discuss.