What is glaucoma?

The term refers to a group of eye conditions which result in irreversible optic nerve damage. It is thought to affect 2% of the population over the age of 40 in the UK.

The condition can affect your vision so gradually that you may not notice any loss of vision until the disease is at an advanced stage. Therefore early diagnosis and treatment are key in minimising or preventing optic nerve damage and limiting related vision loss.



New-Picture-32Glaucoma damage may be caused by raised eye pressure, a weakness in the optic nerve or a combination of both.

Intraocular pressure (IOP) is the tissue pressure within the eye that allows the eyeball to maintain its shape. It is determined by the balance between the production and drainage of clear fluid inside the eye.

Overproduction or obstruction of the fluid can cause an increase in the IOP, which results in damage to the optic nerve.

The optic nerve is the site where all the sensitive nerve fibres around the retina come together to send the visual signal to the brain. It is damage to this optic nerve that causes irreversible visual loss affecting the field of vision.

However, high IOP does not always cause Glaucoma, but if you do experience a higher than normal level of pressure in your eye, you should always consult with an ophthalmologist.


There are a number of different types of glaucoma which can affect the eye, and these are typically classified as follows:

  • Primary Open Angle Glaucoma (POAG)
  • Normal Tension Glaucoma (NTG)
  • Ocular Hypertension (OHT)
  • Acute Angle Closure Glaucoma (AACG)
  • Secondary Glaucoma
  • Congenital Glaucoma
  • Primary Open Angle Glaucoma (POAG)

    POAG is the most common type of glaucoma. It is chronic, progressive and painless.

    It occurs when the drainage system that controls the flow of fluid inside the eye is defective. With POAG, the IOP inside the eye slowly rises, causing damage to the optic nerve.

    This will cause a visual field defect, but often the vision loss is not apparent until it is advanced, as the good eye typically fills in for the damaged one.

    Normal Tension Glaucoma (NTG)

    Normal Tension Glaucoma (NTG) is defined as optic nerve damage occurring in individuals where the eye pressure is within a normal range.

    Ocular Hypertension (OHT)

    Ocular Hypertension (OHT) is where an individual has consistent high pressure with no sign of damage to the optic nerve. From this, we know that high IOP may not always result in glaucoma.

    Acute Angle Closure Glaucoma (AACG)

    AACG is a sight threatening emergency which occurs because of an apposition of the natural lens to the back of the iris.

    This in turn causes fluid to build up behind the iris, blocking the natural drainage and causing a rapid increase in the eye pressure.

    AACG needs immediate treatment, so you should contact an eye professional straight away.

    The symptoms that may occur with AACG include:

  • Pain in the eye
  • Nausea and vomiting
  • Sudden onset of visual disturbance
  • Halos around lights
  • Blurred vision
  • Reddening of the eye
  • Secondary Glaucoma

    This can be any kind of glaucoma, but its cause is secondary in nature, for example as a result of certain drugs (e.g. steroids), other eye conditions (e.g. diabetes) or trauma to the eye.

    Congenital Glaucoma

    This is a rare condition caused by developmental malformation of the eyeball.

    Who is affected?

    Although anybody can get Primary Open Angle Glaucoma, certain individuals carry a higher risk. These include people who:

  • Are over the age of 40
  • Have a family history of glaucoma (You’re 4x more at risk of developing the condition if a close blood relative has the condition e.g. parents/siblings)
  • Suffer from myopia or hyperopia (short/long sightedness)
  • Have blood pressure problems
  • Are of African, Latino, and Asian descent
  • Have diabetes
  • Are regular, long-term steroid/cortisone users
  • Those more at risk of developing Acute Angle Closure Glaucoma include:

  • Anyone with long sightedness or hypermetropia
  • Women (four times more likely)
  • Anyone over the age of 50
  • Glaucoma treatment

    The initial treatment is generally with the use of eye drops that lower the intraocular pressure. Most of the time a drop or combination of drops keep the IOP within the target range.

    Monitoring IOP levels is often key for this disease, and London Eye Hospital offers a range of services, including the revolutionary Triggerfish.

    For more advanced cases, laser treatments and traditional surgery options are all available.

    Find out more about the full range of treatments for glaucoma.

    Why London Eye Hospital

    London Eye Hospital is equipped with the latest diagnostic devices for the early detection of glaucoma and can offer long term regular follow up and treatment for this chronic condition.

    Examinations include:

  • Visual acuity testing
  • IOP check with Goldmann Applanation tonometry (Gold standard)
  • Visual field testing with the Zeiss Humphrey field analyser
  • OCT scanning of the optic nerve
  • Ultrasound Pachymetry
  • Fundoscopy and examination of optic nerve appearance
  • Treatments available for this condition:

  • Glaucoma treatment
  • Book your consultationwith an expert London Eye Hospital eye surgeon.

    Click here to book online now or call us on

    0207 060 2602