Flashes and Floaters: Posterior Vitreous Detachments (PVD) and Retinal Detachments

 
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FLASHES AND FLOATERS: POSTERIOR VITREOUS DETACHMENTS (PVD) AND RETINAL DETACHMENTS 

ANATOMY OF THE EYE
The eye contains a jelly-like substance called the vitreous which fills its centre. This substance is encased in a membrane called the vitreous membrane which is further attached to different points on the retina.

The retina contains light-sensitive cells that detect signals and nerve fibres that send these signals to the brain so that we can see.

 

WHAT ARE THESE FLOATING SPOTS OR LINES IN MY VISION?
Many people often report little spots or lines that appear in their line of sight which they are unable to get rid of. These little spots and lines move around and eventually fade as our brain gets used to them being present. These floating dark spots and lines are what we call “floaters”.

 

WHAT ARE FLOATERS?
The vitreous of the eye contains proteins in the form of collagen fibres which coagulate and form little specs or lines that float around in the eye. This is more common as we age, however, can be present at any time in our life. These floaters can be more noticeable in brighter light conditions as they form shadows on the retina. Floaters remain in the eyes and are not usually removed as the brain adapts to the shadows caused by the floaters, making them less noticeable. 

 

WHAT ARE FLASHES?
Flashes are sparks or strands of light that flicker across your vision. Flashes usually occur when the retina is stimulated. An example of this is when the vitreous membrane pulls away from the retina, tugging the light-sensitive cells and causing what many report as flashes of light.

 

POSTERIOR VITREOUS DETACHMENT
Flashes and floaters can be a sign of a Posterior Vitreous Detachment. This is an age-associated condition that can begin with a sudden increase in the number of floaters. As the vitreous begins to shrink, the vitreous membrane starts to lift away from the retina. Due to the vitreous membrane being attached to the retina at certain points, as it begins to separate from the retina it can pull at it, stimulating the light-sensitive cells and causing flashes.

The vitreous membrane usually separates from the retina with no further complications, however, to confirm this, a dilated fundus examination must be carried out. This allows your Optometrist to complete a thorough check of the retina to ensure that no holes or tears are created when the vitreous membrane pulls away from the retina. Any hole or tear created can lead to a retinal detachment which is a sight-threatening emergency.

Posterior Vitreous detachment
 

Images sourced from West Coast Retina (2020) detailing a Posterior Vitreous detachment

 

RETINAL DETACHMENT
A retinal detachment can have similar symptoms to a PVD in that it can start with flashes and floaters. Further symptoms of a retinal detachment can also include constant flickering in a particular portion of your visual field or eventually a dark curtain moving down over your vision.

A retinal detachment is a sight-threatening condition where the retina begins to pull away from its normal position against the back of the eye. This is usually due to fluid accumulation beneath the retina as a result of a hole or tear.

The faster the detection of a retinal detachment, the better the surgical outcome. This is why it is important to seek professional help when symptoms of flashes, floaters or a curtain over your vision appear.

 

WHO IS MORE AT RISK OF RETINAL DETACHMENTS?

  • Extreme near-sightedness (high myopia)

  • Previous cataract surgery

  • Severe eye injury

  • Previous detachment in the other eye

  • Family history of a retinal detachment

  • Certain degenerative retinal conditions (usually identified during eye examinations)

 
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