Glaucoma

Damage occurs when the eye pressure is high enough to affect the health of the optic nerve, which cannot then carry the full vision signal. This usually begins as a loss of the outer part (periphery) of vision and, if untreated, can progress to tunnel vision and eventually loss of central vision. Once the vision is lost, it cannot be recovered.

There are usually no warning symptoms for glaucoma, therefore, regular eye tests will help detect the onset of the disease. With early detection and treatment, most people have a good vision for life.

There are certain risk factors that have been linked with the development of glaucoma as:

• Age. Glaucoma is uncommon below the age of 40 but becomes much more common with increasing age.
• Family history of glaucoma. There is an increased risk of developing glaucoma if you have a close relative with glaucoma. People with close relatives should get tested by their optician to rule out glaucoma.

• People of African-Caribbean origin have about four times increased risk of developing glaucoma when compared with those of European origin. Also, glaucoma may develop at a younger age.
• Glasses prescriptions. People who are very short-sighted (high myopia) are at increased risk of developing glaucoma. Also, long-sighted (hypermetropia) people are known to be at increased risk of developing angle-closure glaucoma.
• Diabetes. People with diabetes are at increased risk of developing glaucoma, although it is not known whether there is a direct link between the two conditions.
• Blood pressure. Research showed that people with low blood pressure may be at increased risk of worsening of glaucomatous sight loss.

Therefore, it is wise for everyone over the age of 40 to have regular checks at their optician to pick up conditions such as glaucoma.

There are four main types of glaucoma:

1-Primary open angle glaucoma

This is the most common type of glaucoma. It progresses very slowly and it is usually painless. It is called “open-angle” because the angle inside the eye containing the drainage area for fluid looks open when the eye is examined.

However, some people may develop glaucoma despite having normal eye pressure called Normal tension Glaucoma.

On the other hand, some people may have increased eye pressure but have no signs of glaucoma, called Ocular hypertension.

2-Angle closure glaucoma 

This is a less common type that may occur in some people who have what is called narrow angle of the eye. On some occasions, the pressure can suddenly build up to a high level very quickly, called Acute Glaucoma or Acute Angle Closure Glaucoma. This is a very painful and serious condition. This is an eye emergency that required urgent review by an eye specialist.

Treatment consists of medications to lower the eye pressures, drops or medication by mouth or intravenous. This is followed by YAG laser peripheral iridotomy to prevent any further attacks.

3- Secondary glaucoma

This is glaucoma caused by another eye disease that may have led to increased eye pressure as chronic eye inflammation, previous eye surgery, diabetic eye diseases, retinal vein occlusion …etc.

 4- Congenital glaucoma

This is rare but can be serious. It is usually present at birth or develops shortly after birth. It is caused by an abnormality of the eye.

If you have glaucoma, you will need a regular review. This review often includes looking at the appearance of the nerve at the back of the eye and performing some tests as:

• Eye pressure measurement
• Visual field testing
• OCT scan of the nerve: to assess the health of the nerve and if any signs of damage.

Other tests may include:

• Corneal thickness measurement. thick corneas can cause the pressure to seem artificially high and it helps interpret the significance of a high or low pressure
• Gonioscopy. looking at the angle inside the eye with a special lens.

The frequency of follow-up visits depends on the type of your glaucoma and if any signs of progression.

For some people, the diagnosis of whether or not they have glaucoma is not certain at first assessment. They may be identified as “Glaucoma suspect”. This means you do not definitely have glaucoma, but you have some features that look like glaucoma. This could mean that either:

• The appearance of the optic nerve may look like glaucoma
• The visual field test may show some changes that may be similar to those found in people with glaucoma or
• The eye pressure is higher than the average normal but no clear signs of glaucoma.

In these cases, Mr Ellabban will do a detailed examination and some tests as eye pressures measurement, optic nerve scans, visual field test and corneal thickness measurement to help decide if you have glaucoma or not. These tests may need to be repeated to detect if any change over a period of time. Some people may remain the same but some progress to definite glaucoma.

The appearance of the nerve in the back of the eye can vary a lot from one person to another. This means it is sometimes difficult to know whether someone’s optic nerve is normal or abnormal. If the appearance of the nerve does not change over time, it is likely that it is normal for you.

It’s important to understand that being identified as a glaucoma suspect does not automatically mean that you have, or will develop, glaucoma. The risk will depend on many factors and more tests will need to be carried out.

The normal range for eye pressure is around 10-21 mmHg. Some people may have a high eye pressure above the normal range but there is no damage to the nerve and they have a normal field of vision. Those are often called Ocular hypertension.

For some people, the diagnosis of whether or not they have glaucoma is not certain at first. In these cases, your eye doctor will do detailed testing, optic nerve scans, visual field test to help decide and will make a plan with you for any longer-term monitoring you need to see if anything changes.

Some patients may progress to definite glaucoma, but in some people, the tests remain the same without any progression. Those will be reassured and sent back to their optician for annual monitoring after several checks.

Some people have an eye pressure within the normal range but they develop the typical optic nerve and visual field changes of glaucoma – this is known as normal tension glaucoma or low tension glaucoma.

After a detailed eye assessment, Mr Ellabban may advise whether you need to start treatment to achieve better control of the eye pressure.

Glaucoma treatment is often started with eye drops or laser treatment called selective laser trabeculoplasty but in some situations, surgery may be indicated.

1-Eye drops

Many types of eye drops are available to treat glaucoma and control eye pressure. Many patients may require a combination of different drops to reduce their eye pressure to a satisfactory level.

Some patients may develop some side effects from certain drops or they may develop intolerance to a specific drop. Mr Ellabban will be able to advise you on what to do in this situation.

2- Selective laser trabeculoplasty (SLT)

Laser trabeculoplasty is another type of laser treatment used to treat open-angle glaucoma. Laser spots are applied to the trabecular meshwork to stimulate the flow of fluid out of the eye. These treatments can be done in the eye clinic and are generally painless and quick. All laser treatment carries a small risk of complications

3- Glaucoma surgery

There are different types of operations to treat glaucoma, and all of them have the same purpose: to reduce eye pressure. Surgery is often tried when drops or lasers are not as effective in decreasing the eye pressure or there is still progression of the damage to the optic nerve despite maximal treatment. Also, some eye specialist prefers to do surgery in a certain situation to achieve better long-term outcomes.  The main surgeries performed are:

• Trabeculectomy
• Aqueous shunt or tube.
• Minimally invasive glaucoma surgery (MIGS).