Flashes and Floaters

Flashers and floaters are shapes or lights that occur in the visual field, and are commonly experienced by most people during their lifetime. They generally do not indicate a problem, but in some cases may be early symptoms of a more serious issue.


The back part of the eye is filled with a jelly-like material called vitreous. The vitreous is made up of a network of collagen with sugar and water contained within it. When we are young, the vitreous is a solid jelly and if removed from the eye would maintain its shape. With increasing age, the collagen starts to break down and by the time we reach 50 years of age, most of the vitreous is liquid. At this stage, the broken-down collagen forms clumps in the vitreous, resulting in an increasing numbers of small floaters that look like flies or threads in the vision.


The remaining rim of vitreous gel that is adherent to the retina (the back of the eye) will peel off at some stage, as it is no longer supported centrally. On average, this occurs around 60 years of age but can occur earlier, especially if you are shortsighted, or much later in some cases. This process, known as a posterior vitreous detachment (PVD), is a natural process that occurs in everyone at some stage. As the vitreous detaches, it often tugs on the retina, producing flashes of light usually described as arcs of white light in the periphery of the vision. These are most commonly seen in a dim environment or with the eyes closed.



Posterior Vitreous Detachment with floaters and retinal traction


In 99% of vitreous detachments, the vitreous peels away from the retina without any complications. As it does so, larger floaters, more like spiders or cobwebs, may result. As a general rule, some of these new floaters will go away and some will remain long-term. It is important at this stage to have your eyes examined by an ophthalmologist or optometrist to exclude complications that can occur as a PVD progresses. It is also important to keep in mind that floaters and flashes are rarely signs of a serious problem with your eyes, and long-term floaters, while a nuisance, are usually not a sign of eye disease.


In 1% of cases, as the vitreous detaches it can tear a small retinal blood vessel that causes a vitreous haemorrhage, or can tear the retina, causing a retinal hole. These would be diagnosed by your optometrist or eye specialists and treatment would depend on a number of factors.


A mild vitreous haemorrhage can be observed and will usually resolve by itself over a month or so. A more severe vitreous haemorrhage would be treated by a vitreoretinal surgeon with an operation called a vitrectomy to remove the blood and remaining vitreous.


A retinal hole may require laser treatment to seal the hole to prevent the progression to a retinal detachment. A vitreoretinal specialist would also perform this treatment. If the retinal hole has been present for some time then a retinal detachment may have developed and this would require an operation to fix.


Illustrations shown are provided courtesy of the Royal Australian and New Zealand College of Ophthalmologists (RANZCO) and Mi-Tec Publishing. The complete RANZCO patient education pamphlet is available from your ophthalmologist