What causes Flashing Lights?
The vitreous gel which fills the inside of the eye sometimes pulls or tugs on the retina. This pulling causes the appearance of flashing lights or lightning streaks, though there is no flashing light actually present. This same sensation sometimes occurs when you are hit in the eye and ‘see stars’.
When a vitreous separation pulls the gel away from the retina, flashes of light may appear off and on for several weeks. This commonly happens as we grow older and is usually no cause for alarm. On rare occasions, light flashes are associated with a large number of new floaters and even blacking out a part of the field of vision. When this occurs, immediate examination by an ophthalmologist is important to determine if a retinal tear or retinal detachment has developed.
Flashes of light, which appear as jagged lines or ‘heat waves’, lasting 10-20 minutes and being present in both eyes, are likely to be migraine caused by a spasm of blond vessels in the brain. If a headache follows, it is called a migraine headache. However, these jagged lines or ‘heat waves’ can occur without a subsequent headache. In this case, the light flashes are referred to as ophthalmic migraine or migraine without headache.
Floaters or flashes of light do not usually indicate a serious eye problem. However, if a large number develop or if they seem to be much worse over a period of time, an examination by the ophthalmologist is recommended. The examination will involve a careful observation of the retina and vitreous gel. Medical training and experience is required to perform this examination properly.