Quick Facts: Flashes & Floaters

Early symptoms: 

Floaters –Small specks, dots, circles, lines or cobwebs

Flashes – Flashing lights or lightning, often noticed in the corner of vision, even in dark places

Later symptoms:

Retinal Break – sudden increase in black spots like a “shower” of black dots

Retinal Detachment – a “curtain” or shadow blocking part of your vision

Risk factors:

Myopia (short-sightedness), Family history of retinal detachment, History of serious eye injury, previous eye surgery such as cataract surgery


Treatment is not usually needed for floaters. Floaters do not disappear as they are part of the eye, but become less noticeable with time.


What are floaters?

The first thing to know is that floaters are part of our eye.

  • They are formed from the vitreous gel that occupies 80 percent of the eye.
  • The vitreous gel shrinks and also changes from being gel-like to being more watery and stringy over time.This causes the formation of strands which cast tiny shadow on the retina which we see as floaters.
  • The vitreous gel is also attached to the retina initially. However, as it shrinks, it pulls away and detaches from the retina.
  • This may not occur completely, leaving parts of the vitreous gel still attached to parts of the retina.
  • When the attached parts of the vitreous gel pulls on the retina, we notice flashes in our eye. These flashes are not caused by stimulation from light entering the eye, but do to mechanical pull by the vitreous gel on the retina. Hence, flashes can occur in the dark without any surrounding light.

When should you be worried about floaters and flashes?

Floaters and flashes are usually not a worry. However, there are times when you should be seen by an eye doctor urgently:

  • New onset of floaters
  • Sudden increase in floaters
  • Increased flashing
  • Seeing a shadow blocking parts of your vision
  • Seeing a gray curtain covering parts of your vision

These symptoms can suggest either a retinal break or a retinal detachment.

What are Retinal Tears?

The retina is a sheet of light-sensitive cells responsible for receiving light signals so we can see. The retina is attached to the inner wall of the eye.

The vitreous gel is a gel-like substance that is attached to the retina. Over time, the vitreous gel shrinks and becomes watery.

 As the vitreous gel shrinks, it can pull on the retina causing a retinal tear.

What is the symptoms for Retinal Tears?

Symptoms of a retinal tear are similar to floaters. That is why it is important to have your floaters checked to rule out retinal tears. Retinal tears can have symptoms such as:

  • Sudden increase in number of floaters
  • Sudden appearance of flashes

What is the treatment for Retinal Tears?

In the case above, we have a retinal tear with no retinal detachment. The treatment in this case would be to perform laser retinopexy which is a clinic-based laser.


In a laser retinopexy, laser is applied all around the tear. This helps to seal the tear and prevent vitreous from entering through the tear and detaching the retina.

This clinic-based laser can only be performed if there Is no retinal detachment. If there is retinal detachment, surgery will be needed. So it is important to find and treat retinal tears early before they become retinal detachments.

What are retinal detachments?

Retinal detachments are when the retina detaches from the inner wall of the eye. This occurs when retinal tears are not sealed early. This results in fluid traveling through the retinal tear and under the retina causing a detachment.

What are the symptoms of Retinal Detachment?

Symptoms of a retinal detachment include:

  • Seeing a shadow in the side of your vision
  • Seeing a gray curtain moving across your vision
  • Sudden decrease in vision

What is the treatment for Retinal Detachment?

 The best results from treatment occur when the retinal detachment has not affected the center of your vision. This usually means that the retinal detachment is not involving the central part of retina called the macular. This is called a macular on retinal detachment and will have better chance of recovering good vision after treatment. Macular off retinal detachment on the other hand, will not do as well, even after successful surgery. That is why it is critical to identify and treat early.


This involves placing a band around the eye to counteract the force that is causing the retina to be detached. This often also involves drainage of fluid from under the detached retina, allowing reattach ent of the retina. This is surgical procedure that is carried out in the operating theatre.

This surgery involves removal of the vitreous gel that is pulling on the retina. Often a gas bubble may be placed in the eye to keep the retina attached while healing takes place. When a gas bubble is introduced, you may need to keep your head in a certain position for a time. Also you will not be able to fly for a period of time as the high altitudes can cause dangerous increase in eye pressure from expansion of the gas bubble. Over time, the gas bubble will gradually be replaced by your own body’s fluids.

Sometimes, an oil bubble may be introduced instead of a gas bubble. An oil bubble will need to be removed later when the retina has fully attached.

A vitrectomy can be combined with cataract surgery and/or a scleral buckle procedure.

What are the risks of a vitrectomy surgery?

Vitrectomy surgery has advanced in recent years and is a relatively safe procedure.  The risks include:

  • Infection: 1 in 2,000 chance
  • Retinal detachment: 1 in 100 chance
  • Bleeding in the eye: very rare
  • Glaucoma where the eye pressure become high: but usually this responds to treatment with eye drops
  • Cataract where the lens become cloudy: this is readily treatable

What is an epiretinal membrane?

An epiretinal membrane is a thin sheet of fibrous tissue that develops on the surface of the macular and can cause problems with central vision.

 This is because this membrane can contract and cause distortion of the retina. As the macular is responsible for visually demanding tasks such as reading and sharp vision, epiretinal membranes can affect patients quite a lot.

What causes an epiretinal membrane?

 Epiretinal membranes can occur from:

  • Previous retinal tears or retinal detachment
  • Retinal vascular diseases such as: diabetic retinopathy or vein occlusion
  • Previous eye surgery

Epiretinal membranes also increase with age. Studies have shown that 2% of those over 50 and 20% over age 70 can have epiretinal membranes, although most do not need treatment.

What is the treatment for Epiretinal Membranes?

Most epiretinal membranes are fairly stable and do not affect vision. Usually observation is sufficient.

However, if worsening of vision occurs, surgery may be needed. There are no eye drops, medications or nutritional supplements to treat this. The surgery performed is similar to retinal detachment surgery and involves a vitrectomy.

Factors affecting the results of the surgery include:

  • Length of time the epiretinal membrane has been present
  • Degree of traction: or the amount of pulling on the macular by the membrane
  • Cause of the epiretinal membrane: membranes caused by retinal detachment or retinal vascular problems do not do as well

What is a macular hole? 

A macular hole is a tear or opening in the macular, the central part of the retina. As the hole forms, the central vision becomes blurry, wavy or distorted. If the hole extends, the central vision can develop a dark spot or blind spot.

What causes a macular hole? 

Age is the most common cause. Macular holes are more common as we become older. The vitreous gel in our eye shrinks and this causes traction or pulling on the retina and over time can cause a hole to form.

What is the treatment for macular holes?

After macular hole surgery:

  • You will need to keep a face down position for most of the day for a week or more. This is so that the gas bubble will float up against the macular and stay in position for the macular hole to close properly.
  • Air travel, mountain climbing and diving should be avoided as this may cause the gas bubble to expand resulting in eye pressure problems.
  • Vision will be blur immediately after surgery due to the gas bubble. Over time, vision will improve as the gas bubble reduces and healing of the macular hole occurs. The amount of vision you get back also depends on the size of the hole and the length of time the hole was present before surgery.

What is a Central Retinal Vein Occlusion (CRVO)?

 The eye’s retina has arteries and veins which carry blood to and out of the eye. The retinas has one main artery and one main vein.

A central retinal vein occlusion is when the main vein of the retina is blocked. This causes blood and fluid to seep out into the retina. 

The macular (central part of the retina) can also become swollen due to this blockage and cause distortion in central vision.

What are the symptoms of CRVO? 

Central Retinal Vein Occlusion may cause the following symptoms:

  • Sudden loss of vision
  • Seeing floaters: usually due to bleeding into the vitreous gel of the eye
  • Painful eye: this is not common but can occur due to very high eye pressure from glaucoma

Who is at risk of CRVO?

 CRVO is not common in younger people. It generally affects those who are aged 50 over.

Certain conditions can put you at higher risk: 

  • High blood pressure
  • Diabetes
  • High cholesterol
  • Glaucoma

What is the treatment for CRVO? 

Not all CRVO cases need active treatment and may only require observation. This is especially if the blood flow is not severely compromised. This type of central retinal vein occlusion is called a non-ischaemic CRVO.

In other cases, the blood flow is significantly blocked and this leads to poor circulation to the retina. This type of central retinal vein occlusion is called a ischaemic CRVO. In ischaemic CRVO, laser to the retina called panretinal photocoagulation is needed to reduce the oxygen requirement of the retina. This is needed to prevent abnormal blood vessels from growing in a process called neovascularization. Neovascularization can lead to serious complications such as vitreous haemorrhage (bleeding in the eye) and glaucoma (high eye pressure).

In some cases, CRVO may cause swelling in the macular (central part of the retina) called macular oedema. In such cases, medication injections in the eye called anti-VEGF injections may be recommended. Occasionally, steroid injections may also be used.