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Eyeing floaters
and flashes

Dr Elaine Huang

MBBS (S’pore), FRCS (Edinburgh),
MRCS (Edinburgh), MMed (Ophthalmology),
FAMS (Ophthalmology) (Gold Medallist)

Senior Consultant Ophthalmologist
Eye Max Centre

How to look out for possible complications of the retina from seemingly harmless eye conditions.

You may have noticed them since you were young, or they may have just come into view as you got older, but floaters and flashes are really quite common and, most of the time, are nothing to worry about. However, being aware of red flags can allow early diagnosis of conditions that require treatment. 

Floaters, as the name suggests, are specks that float about in your field of vision. They may appear as  dots, cobwebs, circles or squiggly lines and are more obvious against a bright background such as when  you are looking up at the sky or a white computer screen. They drift about when you move your eyes  and dart away when you try looking at them directly.  If you have ever looked at specks of dust floating on a drop of water under a microscope, they are similar to what floaters look like. 

Flashes, on the other hand, are perceptions of flashing lights, like streaks of lightning or a flash of the camera, which are made worse with rapid eye movements.

floaters dark spots

Ageing gel conditions

Floaters and flashes are caused by conditions associated with the vitreous, a colourless gel-like substance that fills up the space within the back of the eye. 

Floaters can be due to age-related changes. As we grow older, the vitreous and its collagen fibres shrink and the gel becomes stringy. Because these strands are located in front of the retina, they can cast little shadows that become more perceivable under certain lighting conditions, causing the floater phenomenon. 

Collapsing vitreous also causes the gel to pull away from the retina as it shrinks towards the centre of the eye. This traction can stimulate the retina to cause the sensation of flashing lights. Once the gel has detached, the pulling stops and the flashes go away. 


When to worry 

Even though they are usually harmless, you should take note if there is a new onset or a sudden increase in floaters from what you usually experience – especially if they appear immediately after flashes of light or are associated with blurred vision. These abnormalities may indicate the possibility of retinal tears. If you have recently had eye trauma or surgery, or have high myopia, the likelihood increases. 

Likewise, sudden showers of flashes can point to abnormally strong pulls on the retina or retinal blood  vessels; and are worrying because they can cause retinal tears or bleeding in the eye. When the retina tears, retinal detachment and loss of vision can result. 

If detected early however, retinal tears are treatable by laser, but when the retina detaches, surgery is usually required.

Another sudden cause of floaters or vision loss is bleeding into the vitreous gel in uncontrolled diabetics with abnormal new blood vessel  growth on the retina. Less common are floaters arising from inflammation or infection at the back of the eye, usually recognised by accompanying pain and redness of the eye.

If all underlying problems have been excluded and the conditions are determined to be caused by age, no treatment is necessary. Floaters may be very bothersome initially, but you will subconsciously learn to ignore them and they will soon become less noticeable.