Information

Glaucoma

Below is information about the condition and how best to treat it. A PDF version is available at the bottom of the page.


What is it?

Glaucoma is the given name to a group of eye conditions where the optic nerve is damaged at the point where it leaves the eye. The optic nerve carries images from the retina, the light sensitive membrane attached to the inner surface of the eye, to the brain.

There are four main types:

  • Chronic glaucoma (slow onset)
  • Acute glaucoma (sudden onset)
  • Secondary glaucoma (caused by another eye condition)
  • Congenital or development glaucoma (a condition is babies caused by malformation of the eye)

Regular eye tests are important. Chronic glaucoma affects one percent of people over 40 and five percent of people over 65. The risk of glaucoma increases with age and if left untreated it can cause blindness.


What causes it?

The eye needs a certain amount of pressure to keep its shape. This balance of pressure is maintained by the production of watery fluid (aqueous humour) in the ciliary body and its eventual departure from the eye through tiny drainage channels. Glaucomatous damage can be caused by a rise in eye pressures but damage s due to be a weakness in the optic nerve. Most cases have a combination of these elements:

  • Chronic glaucoma is more common with increasing age. It is uncommon in those under 40
  • People of African or Afro-Caribbean origin are more at risk, with inset at an earlier age and of greater severity
  • Those with a high degree or short-sightedness, diabetes, family history of glaucoma or those who are on certain medications are more at risk

What are the symptoms?

Chronic glaucoma often has no symptoms and the eye may seem normal. This isn't painful and at first your vision may be unaffected. Over time glaucoma never damage reduces the field of vision, causing a blind spot, or “scotoma”. This appears as an arc shape near the centre of vision; although you may not notice early field loss as your other eye compensates. If left untreated this blank area spreads outwards and inwards giving the effect of tunnel vision.

Acute glaucoma can happen quickly and symptoms can include pain, discomfort, redness and haloes around lights, as well as loss of vision. It needs to be treated immediately.


How is it detected?

Your Optometrist will carry out tests to see if there are any signs of glaucoma. These are:

  • Measuring your eye pressure (Intra-ocular pressure)
  • Examining the optic nerve head by viewing the retina using an optical microscope (slit lamp) or using a special magnifying lens or an ophthalmoscope
  • Measuring your field of vision with a machine that shows a series of flashing lights to detect any areas of scotoma away from your central vision

How is it treated?

Your Optometrist will refer you to an Ophthalmologist at the hospital for further diagnosis and any required treatment.

Treatment is usually by using eye drops to reduce the pressure in the eye by opening up the drainage channels or reducing the amount of fluid being produced. In some cases an operation or treatment by laser may be required.


What can I expect to happen?

Although damage caused by glaucoma cannot be repaired, with early diagnosis, regular observation and treatment damage can usually be kept to a minimum. If you do experience some sight loss your Optometrist will be able to advise will be able to advise you on low vision aids and your Ophthalmologist will advise whether you are eligible to register as sight impaired.

The eye test is important for the detection of many eye diseases. If you are over 40 and have a family history of glaucoma, you should have an eye test every 12 months.


If you have any queries please feel free to contact us.