If the vitreous gel shrinks and pulls away from the wall of the eye, the retina can tear. This sometimes causes bleeding inside the eye that may appear as new floaters.
A torn retina is always a serious problem, since it can lead to retinal detachment. You should see your ophthalmologist (Eye M.D.) as soon as possible if you suddenly see an increase in the size and number of floaters, and/or you suddenly see flashes of light.
Some people experience flashes of light that appear as jagged lines or "heat waves" in both eyes, often lasting 10 to 20 minutes. These are not flashes from the vitreous gel pulling on the retina; instead, these types of flashes are usually caused by a spasm of blood vessels in the brain, called a migraine. If a headache follows the flashes, it is called a migraine headache. However, jagged lines or heat waves can occur without a headache. In this case, the light flashes are called an ophthalmic migraine, or migraine without headache. Contact your ophthalmologist if you experience these symptoms.
If you notice other symptoms, like the loss of side vision, you should see your ophthalmologist.
Next Page: Floaters and Flashes Diagnosis