What are eye floaters and flashing lights?
Floaters and flashing lights are common visual symptoms, particularly as we get older. In most cases they are harmless, but a sudden change in floaters or flashes can sometimes be a warning sign of a retinal tear or retinal detachment and should be checked promptly.
What are eye floaters?
Floaters are small shapes that appear to move across your field of vision. They may look like dots, specks, circles, lines, strands or cobwebs and are often most noticeable when looking at a plain, light-coloured background such as a clear sky, computer screen or white wall.
Floaters tend to move as your eyes move and may appear to drift away when you try to look directly at them.
What causes floaters?
The inside of the eye is filled with a clear, gel-like substance called the vitreous. At the back of the eye is the retina, a thin layer of light-sensitive tissue that plays an essential role in vision.
As we age, the vitreous gradually changes consistency and may shrink or pull away from the retina. Small strands or clumps within the vitreous can cast shadows onto the retina. These shadows are what we see as floaters.
This age-related process is common and is often referred to as a posterior vitreous detachment (PVD). Floaters associated with these changes may be quite noticeable at first, but many people become less aware of them over time.
However, a sudden appearance of new floaters, a significant increase in floaters, or floaters accompanied by flashing lights should be assessed promptly by an optometrist or ophthalmologist.
What can be done about floaters?
Most floaters do not require treatment. Although they can initially be distracting, they often become less noticeable as the brain adapts to them.
If a floater temporarily moves into your direct line of sight, moving your eyes may cause it to drift to another part of your vision.
If floaters are new, suddenly increase in number or begin to interfere with your vision, it is important to have your eyes examined to determine the cause.
What are flashing lights?
Flashing lights, sometimes called flashes or photopsia, may appear as brief flashes, sparks or lightning-like streaks in your vision. They are often noticed towards the side of the field of vision and may still be visible when the eye is closed.
What causes flashing lights?
Flashes can occur when the vitreous gel inside the eye pulls or tugs on the retina. This stimulates the retina and creates the sensation of seeing light even though there is no external light causing the flash.
This can occur during normal age-related changes to the vitreous, including posterior vitreous detachment. However, pulling on the retina can occasionally cause a retinal tear, which may develop into a retinal detachment if left untreated.
Flashing lights and migraine
Some visual disturbances are associated with migraine rather than the retina. A migraine aura may cause shimmering lights, zigzag patterns, flickering or other visual effects that usually develop gradually and may affect vision in both eyes. These symptoms can occur before or during a migraine headache, or sometimes without a headache at all.
If you experience visual symptoms for the first time, if they are different from your usual migraine symptoms, or if you are unsure whether the symptoms are coming from one or both eyes, it is important to have them assessed.
When should you be concerned about floaters and flashes?
Most longstanding floaters are harmless. However, sudden changes can sometimes indicate a retinal tear or retinal detachment.
Seek urgent eye care if you experience:
- a sudden onset of new floaters
- a sudden increase or “shower” of floaters
- new or frequent flashes of light
- flashes and floaters occurring together
- a dark shadow, curtain or veil moving across your vision
- loss of part of your peripheral or central vision
- a sudden or significant change in vision.
A retinal tear can sometimes be treated before the retina detaches. A retinal detachment is a serious eye condition that requires urgent medical treatment to reduce the risk of permanent vision loss.
If you develop new floaters or flashing lights, particularly if the symptoms appear suddenly or are accompanied by a change in your vision, contact your optometrist promptly for advice and assessment.
When in doubt, check it out!
