Flashes and Floaters


‘Flashes and floaters’ refer to abnormal shapes and lights that you may see as you look at the world around you. Floaters appear like specks, dots, squiggly lines or cobwebs “floating” about in your field of vision. Flashes refer to flashes of light which you might see without any external stimulus. Floaters are common and they may be harmless, especially if you’ve had them for a long time and they don’t affect your vision. Floaters can become less noticeable over time, whereas flashes may disappear. If they appear suddenly (including after eye surgery/injury), increase in number or are accompanied by other eye symptoms such as pain or blurred vision, it is important to have these checked-out by an eye care practitioner.


Flashes and floaters can affect what a person sees in a number of different ways. Flashes or flickering can appear and are most prominent in dimly lit environments.  Floaters can appear as small specks, cobwebs, clouds, squiggly lines or dark dots in your vision and are most apparent when looking at a bright background, such as a clear blue sky. More significant symptoms which may indicate a more serious problem include a sudden decrease of vision along with flashes and floaters, a veil or curtain that obstructs part or all of the vision or a sudden increase in the number of floaters. If you experience any of these symptoms, you should seek immediate advice from an eye care professional.


Flashes occur when the vitreous gel which is contained inside your eye pulls on the sensitive retina tissue at the back of the eye.  This movement causes what looks like flashing streaks. These flashes may be seen from time to time over a few weeks or months and are more common in older people. If the flashes appear very suddenly, it is important to have them checked out by an eye care professional urgently. Occasionally, flashes of light are caused by neurological problems such as a migraine. When related to a headache, the flashes of light are seen in both eyes for approximately 20-30 minutes and may be associated with a headache. Floaters are caused by tiny bits of vitreous gel or cells that cast shadows on the retina. As individuals get older, the vitreous gel shrinks leading to the appearance of floaters. In some cases, the vitreous gel thins and may separate from the back of the eye. This is called posterior vitreous detachment (PVD), which is a very common and usually harmless condition. Other causes of floaters include the leakage of pigmented cells from behind the retina and the loss of blood cells from nearby blood vessels into the vitreous gel. There are other more serious causes of flashes and floaters. Retinal tears, retinal detachment, infection, inflammation, haemorrhage or an injury such as a blow to the head may also cause floaters and flashes.


It is important to notify your doctor immediately if you notice a sudden shower of floaters, new light flashes, a veil or curtain obstructing vision, or any other sudden change. In an eye examination, the ophthalmologist will dilate your pupils with drops and examine the vitreous gel and retina inside the eye with an ophthalmoscope. For further examination of the eye, an ultrasound of the eye may be performed. It is important to periodically assess the vision of each eye. Many problems can be detected early by simply comparing both eyes. To test your vision: • Cover one eye and pick a point to look at straight ahead • Note the quality of your central and peripheral vision, noting any change • Look for any obstructions, veils or curtains in your peripheral vision • Watch for floaters, flashes • Note the duration and intensity of the symptoms • Cover other eye and repeat • Report any new symptoms or changes in vision to your eye doctor


It is important to note that not all flashes or floaters will require treatment. Sometimes, by simply looking either up or down, floaters can be moved out of the field of vision. If posterior vitreous detachment (PVD) causes floaters to significantly obscure vision, surgical removal of the vitreous gel may be required. However, this treatment is rarely needed since floaters typically become less bothersome over a period of weeks to months as they settle below the line of sight. If the flashes and floaters are related to another medical condition, the treatment approach may be tailored to the condition. General eye check-ups are important for people with Flashes and Floaters, as these individuals may still be at risk of developing other kinds of eye problems that affect the general population, some of which may be treatable. No matter what level of vision a person may have, it is important to look after the eyes. To find out more about what can be done to take care of the eyes on a daily basis, please visit our Tips for Good Eye Health.


Researchers are currently examining a type of laser treatment for floaters as part of a clinical trial. They hope to use this treatment to make the floaters smaller, allowing them to drop to the bottom of the vitreous cavity and out of the field of vision. This study is expected to complete at the end of 2020. Information about clinical trials can be found on the clinical trials website and can be searched by condition and trial location.


Receiving a diagnosis can be overwhelming for anyone, but this is not a journey that you have to make alone. There are many groups and resources available to provide support for people living with Stargardt Disease. Fighting Blindness offers a free and confidential counselling service (Insight Counselling). For further information please contact insight@fightingblindness.ie or call 01 6746496. We also offer support groups for people with a visual impairment to share their feelings and experiences with others facing the same challenges. Please consult the support groups section of our website here to access the latest timings and days for the various support groups we offer. For further information please contact insightgroups@fightingblindness.ie or call 01 6746496.


Féach provides support for parents of children living with sight loss in Ireland. ChildVision is the national education centre for children with sight loss in Ireland. NCBI (National Council for the Blind in Ireland) provides support and services for people living with sight loss in Ireland. Irish Guide Dogs for the blind helps individuals and their families to achieve improved mobility and independence.    


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