Glaucoma - the thief of sight

Eye Institute offers many treatment options for glaucoma, including eye drops, tablets, laser treatment and glaucoma surgery. The specialists at Eye Institute are acknowledged leaders in their field and will discuss the safest and most effective choice for each individual’s glaucoma.

You may have glaucoma but you’re far from alone. Around 30,000 other New Zealanders have this condition. If it is not treated, glaucoma can impair your eyesight. However when glaucoma is recognised and treated early, loss of sight may be prevented. The average person over the age of 40 has about a 1% chance of developing glaucoma. However, those who have a parent with glaucoma have alot greater chance of developing the disease. Everyone over 40 should be checked for glaucoma at least every five years, and those with a family history more frequently. You probably have many questions about glaucoma and its treatment. At Eye Institute we’re always happy to answer your questions at any time. But in the meantime, we hope this booklet will help you understand the condition. Modern glaucoma treatments are very effective. Understanding the disease will help you to follow the glaucoma management programme prescribed for you.

FIGURE 1: ANATOMY OF THE EYE

How your eye works
The eye functions much like a camera. The cornea is the clear tissue at the front of the eye. Through the cornea you can see the iris, which is the coloured part of the eye. The black hole in the centre of the iris is the pupil, which can vary in size to regulate the amount of light entering the eye. The lens is located behind the pupil and cannot be seen without amicroscope.

The cornea and the lens combine to focus light rays on to the retina at the back of the eye. The retina converts the light into electrical impulses which then pass up the optic nerve to the brain.

The front part of the eye is filled with a fluid which is called aqueous humour. Its production, and drainage out of the eye are controlled so that the eye is maintained within a normal pressure range. In glaucoma the pressure is often (but not aways) raised, usually because of abnormalities in the drainage canal. The place where the optic nerve leaves the eye is called the optic disc, and this can be seen in the eye using specialist instruments. An abnormal-looking optic disc is an early sign of glaucoma.

NORMAL OPTIC DISC

GLAUCOMATOUS OPTIC DISC

Glaucoma - a disease of the optic nerve
Each optic nerve is made up of almost a million fibres which originate in the retina. In glaucoma, some of these nerve fibres become damaged. This results in blind areas in the vision which in the beginning affect the peripheral or side vision. If not treated, more and more nerve fibres become affected, causing a shrinkage of the field of vision which leads to tunnel vision and eventually to blindness. Fortunately this rarely occurs if glaucoma is treated early.

Types of Glaucoma

• Open-angle glaucoma - This is by far the most common type and is what we have been discussing so far. Early detection and treatment are the best way to prevent loss of vision.
  
• Acute closed-angle glaucoma - This occurs when there is a sudden blockage of the drainage canals in the eye. As a result, the pressure builds up rapidly causing blurred vision, coloured halos around lights, headache, and often severe pain. This is an emergency situation since the rapid increase in pressure can severely damage the optic nerve in a few hours.

• Not some kind of cancer or tumour
• Not an infection
• Not caused by too much reading or reading in poor light
• Not caused by improper diet
• Not caused by wearing contact lenses

AN ABNORMAL VISUAL FIELD WITH ALMOST NO VISION ABOVE CENTRE.

HEALTHY EYE

UNHEALTHY EYE WITH GLAUCOMA

• Glaucoma Eye Drops
  To be effective, eye drops must be taken regularly and continuously. There is an increasing range of eye drops available which lower the pressure in the eye and thus slow or halt the progression of glaucoma. Some function by reducing the production of aqueous humour, while others increase its outflow. Some of these drops have a long duration of action and need to be used only once daily, while others need to be used twice or four times daily.
  
  Your doctor will advise you which drops are best for your individual situation. If the drops do not adequately control your glaucoma, stronger or additional drops can be tried.
  
  Many but not all cases of glaucoma can be controlled for a long time with appropriate eye drops. However if your glaucoma worsens despite using eye drops, then laser treatment or surgery may be needed.
  
  
• Laser Treatment at Eye Institute
  Laser trabeculoplasty is a relatively minor operation in which some of the blockages to the drainage canals are opened by focusing an intense beam of light on to the clogged drainage canals. The procedure is performed under local anaesthetic.
  
  
• Glaucoma Surgery at Eye Institute
  This involves creating a new channel for fluid to drain out of the eye. It is usually very effective in reducing the pressure in the eye and indeed after the surgery there may be no need for further medications.

To make an appointment, or to find out more information, fill out our enquiry form, or contact Eye Institute's friendly team on free phone 0800 393 527.



Affiliated provider benefit to Cataract Patients
- no need for prior approval
- no money up front for surgery
- Southern Cross pays us directly