This literally means a blockage of the major vein of the eye.

This leads to leakage of blood and fluid into the retina. If this involves the macula, then vision is

In severe cases, blood flow supplying the retina is compromised (“ISCHAEMIA”).

Risk Factors

  1. High BP
  2. Age
  3. Diabetes
  4. Cigarettes
  5. Glaucoma
  6. Blood disorders


  1.  Reduced Vision


  1. Fluorescein Angiogram – A special yellow dye is injected into the vein. It then enters theblood supply of the eye showing the blockage and its severity.
  2.  OCT – This device gives a “snapshot” of the macula using light waves. It gives a high resolution image of the macula and is very helpful in monitoring any improvement with treatment.

Severity of Disease

“1/3 rule” 1/3 – mild  1/3 – moderate  1/3 – severe

Mild cases: (Nonischaemic)

  • Usually associated with good vision
  • Majority will be stable
  • 1/3 will progress to severe disease

Moderate cases:

Often there is mild reduction of vision.

May improve or progress to severe disease.

Severe cases: (Ischaemic)

  • Usually associated with poor vision
  • Prognosis is guarded
  • High risk of developing “Neovascular Glaucoma” which can lead to a blind and painful eye


1. Medical Treatment:

Your GP will be asked to optimise your BP, BSL, cholesterol and other risk factors.

2. Observation:

Mild cases where there is good vision require observation only. As 1/3 of cases here can progress to the severe form, patients should report any deterioration of vision to their doctor.

Treatment Aim

Treatment is designed to improve vision by drying the macula until such time as collaterals are formed. Here the eye produces blood vessels to bypass the blockage. This can take 18 months to 2 years.

In severe cases, the aim is to prevent a painful eye occurring.

3. Intravitreal Injections

Here, drugs are injected into the eye to treat the blockage. There are 2 main drugs used. These are AVASTIN and TRIAMCINOLONE. Both have their pros and cons and your doctor will discuss which drug is most appropriate for you.

These drugs work to reduce the blood and fluid at the macula thus improving vision. Their effect wears off over time and multiple injections may be required.

4. Laser Treatment

In severe cases, there is a high risk of “Neovascular Glaucoma” leading to significantly increased eye pressure. This can lead to a painful and blind eye.

This can be prevented by laser treatment. Often, 4 sessions of laser will be required. Laser reduces the risk of getting a painful eye but will not improve vision.


  • Mild cases can resolve with good results
  • Severe cases carry a guarded prognosis

Click here to download our Central Retinal Vein Occlusion Fact Sheet