Dr Goh Kong Yong, an ophthalmologist at Mount Elizabeth Novena Hospital, explains what floaters and flashes are and how they can affect your vision.

What are floaters and flashes?

Often described as looking like ‘flies’, ‘cobwebs’ or ‘dots’, you may sometimes see floaters in your field of vision. Like the name suggests, these tiny specks float about like dust as you move your eyes. These floaters are more obvious when you see them against a bright sky or a white screen on the computer.

Flashes appear as lightning streaks that shimmer around the edge of your field of vision. They can last for a few seconds or a few minutes. They may appear on and off for several weeks or months, and are generally more obvious in dim areas.

What causes floaters and flashes?

Floaters are tiny clumps of cells inside the vitreous (a jelly-like fluid) that fills the inside of the eye. They form as the vitreous gel degenerates, but don’t worry – this is part of the normal ageing process.

As these cells float in the vitreous gel, they cast shadows on the retina, which is the light-sensing inner layer of the eye. When we move around, the currents in the vitreous move these cells about, causing us to see floaters.

More rarely, these floaters are caused by blood or inflammatory cells. This is more common in people with diabetes or who already have an inflammatory condition of the eye.

As you age, the vitreous gel liquefies, which is why you might start seeing flashes of light. With each eye movement, the vitreous gel moves and pulls on the retina, setting off an impulse seen as a flash.

Can I do anything to prevent floaters and flashes?

Currently, you can’t do anything to prevent or remove floaters and flashes. However, they usually become less obvious with time.

Should I be worried about them?

Floaters and flashes are very common. Luckily, they are usually harmless, but you may find them a bit irritating.

Floaters and flashes are only a matter of concern if the vitreous pulls on the retina and tears it. Subsequent bleeding may appear as an intense ‘shower’ of new floaters. If left untreated, a retinal tear can cause the retina to fully detach from the eye, which may lead to blindness.

If you experience a sudden appearance or increase of floaters in the eyes, consult an eye doctor immediately to rule out a tear, or to get timely laser surgery to repair it.

If you see a dark or translucent ‘curtain’ across your eye after sudden floaters and flashes, this may indicate that your retina has detached.

If you experience these symptoms, seek medical advice immediately to lower your risk of any permanent damage. And remember: an annual eye check-up by an eye specialist is vital to maintain your eye health, especially if you are short-sighted. Like with all health issues, intervening early gives you the best chance of recovery!

Article contributed by Dr Goh Kong Yong, ophthalmologist at Mount Elizabeth Novena Hospital