Flashes and Floaters
What are flashes and floaters?
As we grow older, it is more common to experience flashes when rising to your feet after a long night’s sleep due to changes in blood pressure rather than a posterior vitreous detachment. Another type of flash is that which is associated with migraines. It appears as jagged lines or “heat waves” in both eyes forming a semicircle arc in the peripheral vision, typically up and out, often lasting 10-20 minutes. These flashes are actually caused by the spasm of blood vessels in the brain and possibly the eye. If the flashes are preceded by a headache, this is called a classical migraine. If there is no headache associated with the arc of light, it is referred to as an ocular migraine.
When should I see an Ophthalmologist?
The appearance of floaters or flashes may be alarming, especially if they develop suddenly.
If you are over the age of 45, you should be seen right away by your ophthalmologist (Eye M.D.).
If you notice a sudden onset of flashes with or without floaters, you should also be seen to rule out the possibility of a retinal tear.
If you develop a sudden onset of flashes preceding a migraine headache, you should also visit you local Eye M.D.
While not all flashes and floaters are serious, you should always have a full dilated eye examination by an ophthalmologist to make sure there has been no damage or potential damage to the retina.
What should I be alarmed about?
Always notify your Ophthalmologist quickly if you see:
An onset of new floaters or a shower of floaters
Increased frequency of flashing or the onset of new flashes when they were previously been absent.
Onset of a curtain or veil that obstructs part or all of your vision.
What are floaters?
You may sometimes see small specks, clouds, or cob webs moving in your field of vision. These entities are called floaters. They are most noticeable when looking at a plain, light colored background, like a blank white wall or a clear blue sky. Floaters are actually tiny clumps of gel in or areas of dehydration of the part of the eye called the vitreous, which is the clear jelly-like fluid that fills the inside of your eye. Although the floaters appear to be in front of the eye, they are actually floating inside. What you are actually seeing is the shadow of these opacities that are cast onto the retina, the nerve fiber layer at the back of the eye that senses light and allows you to see. They may produce many different types of shapes. The most commonly reported shapes are gnats, semi-circles, lines, clouds, or cobwebs.
What causes floaters?
When people reach middle age, the vitreous gel may start to thicken or shrink, much like jelly, forming these clumps or strands. As it proceeds to shrink, it also begins to pull away from the back of the eye creating a space between it and the retina. This process now is called a posterior vitreous detachment, not to be confused with a retinal detachment.
Posterior vitreous detachment is more common for people who:
Are nearsighted
Have undergone cataract surgery
Have had laser surgery following cataract surgery
Have had an inflammation or infection within the eye Posterior vitreous detachments have a higher incidence with
increasing age. The approximate incidence correlates with one’s age. So; if you are 50 years old, about 50% of your peers will have similar symptoms. If you are 80, 80% of your peers have this condition.
What causes flashes of light?
As the vitreous separates from the retina, it may produce traction on the retina in areas that are more firmly attached. When the vitreous pulls on the retina, the mechanical irritation that is created is converted into light by the retina in the form of a strobe of light (flash) or a streak of light (lightening or shooting star). You may have experienced the same sensation if you have ever been hit in the eye and seen “stars”. The flashes of light can appear off and on for several weeks or months.