Bono is a well known Irish person who suffers from glaucoma.
The risk factors for Glaucoma include
Elevated pressure in the eye, known as Intraocular pressure. Increased pressure within the eye, puts pressure on the optic nerve, resulting in damage.
Family history of Glaucoma
Race or Ethnicity; Glaucoma is found to be more prevalent in some races or ethnic groups
Age; as we age, due to changes in the structures of the eye, we become more prone to developing Glaucoma.
It is important to know your risk factors.
Elevated pressure is a risk factor for Glaucoma.
In Ireland it is estimated the 50% of people with Glaucoma remain undiagnosed. This is because Glaucoma is a complex disease and can be difficult to detect. In the past Glaucoma was always associated with high pressures within the eye, however, we know now, that Glaucoma can still occur when the pressures are low or normal.
There are four main types of Glaucoma
1.Chronic Glaucoma, where the Glaucoma is present for many years but is undetected because the pressure in the eye is rising slowly or remains normal. This is the most common type of Glaucoma and unfortunately if not diagnosed early, significant damage can occur to the field of vision before it is diagnosed.
2.Acute Glaucoma; This type of Glaucoma comes on suddenly, is very painful and is characterised by a very red eye which waters excessively. Vision can become cloudy and you may see haloes or rainbows around lights. This needs to be treated quickly as it can cause damage to your vision.
3.Secondary Glaucoma; This type of Glaucoma occurs when there is another problem already happening in the eye, such as advanced diabetic eye disease.
4.Developmental Glaucoma; this is a type of congenital Glaucoma, where the baby is born with Glaucoma due to a problem with the way the eye has formed when the baby is developing in the womb. This can be very serious as requires urgent treatment, however the outcome can be very good once the condition has been identified and is being managed.
The biggest problem with Chronic Glaucoma is that there are no symptoms and it is difficult to detect. Most people with this type of Glaucoma have no symptoms until vision loss has occurred, by which time it may be too late to halt progression of the disease.
Glaucoma affects our vision by killing off the nerve fibres in the retina which carry the important visual information from the retina to the optic nerve and into the brain. Vision loss occurs in a particular pattern, starting out on the peripheral visual field, gradually moving inwards to eventually affect central vision.
Example of a normal Optic disc.
Glaucoma damages the nerve fibres at the Optic disc, causing changes in the appearance of the disc as shown above.
Your Optometrist will assess your chances of having glaucoma by looking at your risk factors, measuring your pressures and carefully examining your optic disc. Your optometrists may wish to take photographs of the back of your eye, to monitor any possible changes at the disc. Chan
Changes in the appearance of the optic disc often precede visual field loss, so, careful optic disc assessment is a very important part of the Glaucoma examination. The Optometrist may also wish to do a special field test on you to see how well your visual field is working. They will look for specific signs that your visual field is being affected which could be as a result of Glaucoma.
Optometrists cannot just look at the results from your pressure test. This is because some people have naturally high pressures, while their visual field and optic discs remain perfectly healthy. However, these people need to be reviewed regularly to ensure nothing changes. Other people may have perfectly normal pressures, yet other changes occurring at the back of the eye cause damage to the optic disc and result in visual field loss.
The three key tests for a Glaucoma examination with an Optometrist are:
- Repeat pressures, preferably with a technique called Contact tonometry as this is more accurate in measuring IntraOcular Pressure.
- Repeat Visual Fields; regular examination of the visual field will help in identifying early changes in the visual field consistent with those expected in Glaucoma.
- Optic Disc assessment; careful examination of the optic disc, preferable using a special magnifying lens which allows the optometrist to view the optic disc at the back of your eye in 3D, again, the optometrist will be looking for specific signs of damage to the rim of the optic disc which are consistent with Glaucoma.
If you are diagnosed with Glaucoma there are many ways in which it is treated. Your Eye Doctor who specialises in treating Glaucoma will decide on what type of treatment is most effective for you and your type of Glaucoma. They may treat it with medications such as b-blockers, carbonic anyhdrase inhibitors or prostaglandins...or a combination of a number of drugs, Your Eye Doctor will also look carefully at what medications you currently take, as this may contraindicate certain Glaucoma drugs.
The Eye Doctor may decide the best option for your type of Glaucoma is to use laser or in some cases, surgical treatment may be more appropriate.
Most importantly, early detection of Glaucoma is essential. By having regulsr eye tests with your optometrists, we can detect early and subtle changes in your eyes and how they look, which give us important information about your risks of having the disease. The key to treating and managing Glaucoma is early intervention to prevent vision loss advancing. One visual field damage has occurred, this cannot be reversed, but further damage can be prevented with prom[pt and appropriate treatment.