Glaucoma

Your guide to glaucoma types, symptoms and treatments.

What is glaucoma?

Glaucoma is a group of diseases that affect the optic nerve, which is the nerve that communicates information from the eye to the brain. Commonly known as “the silent thief of sight,” the initial vision loss is mainly peripheral and is not readily noticeable. Central vision and reading vision are usually spared until later. Therefore, you may remain asymptomatic until later in the disease process when most of the vision has already been irreversibly lost. Most, but not all of these diseases are characterised by raised pressure in the eye (intraocular pressure) which causes characteristic optic nerve damage, resulting in irreversible loss of vision. However, the level of this pressure that causes damage can vary in different individuals.

To understand glaucoma, traditionally a healthy eye constantly produces fluid to keep itself nourished, and has a built-in drainage system for fluid to exit the eye. If the eye produces too much fluid, or the drainage system malfunctions, fluid can build up and cause an increase in pressure inside the eye. Eventually, the pressure can damage the optic nerve and lead to permanent, irreversible vision loss.

Glaucoma

What are the types of glaucoma?

Open-Angle Glaucoma

This is the most common type of optic neuropathy in which there is progressive damage to the optic nerve, and the nerve tissue in the optic disc becomes increasingly thinned over time. Vision gradually becomes affected, with peripheral vision generally being affected before central vision. Damage to the optic nerve in OAG is most commonly due to high pressure within the eye ball, although this is not always the case.

Ocular Hypertension

Some patients have elevated intraocular pressures but no evidence of damage to the optic nerve or their vision. These patients are considered to have ocular hypertension. They may be more at risk of developing open angle glaucoma in the future and require close monitoring or even prophylactic treatment to slow the development of glaucoma. Your eye specialist or primary care optometry can closely monitor this for progressive changes to your optic nerve and vision.

Angle-Closure Glaucoma (ACG)

In ACG, there are two forms which can cause damage to the optic nerve, acute and chronic. In the chronic form, the normal flow of fluid (aqueous humour) becomes increasingly impeded due to underlying anatomical variation and/or cataract formation, causing the intraocular pressure to rise. In time, this elevated pressure will cause damage to the optic nerve if left untreated. Factors include small eyes (Hyperopia or far sightedness), older age, females, Asian & Indian ethnicity and blood relative with angle-closure glaucoma.

The acute form of the disease is characterised by a sudden, dramatic increase in intraocular pressure due to the closure of the drainage angle. The fluid has no alternative channel to escape through and this can cause severe eye pain, redness, blurred vision and haloes around lights. Headaches, nausea and vomiting may follow. This is a serious eye emergency and requires prompt treatment by your eye specialist and can cause permanent blindness if not treated immediately.

How is glaucoma detected and managed?

The intraocular pressure of the eye is measured and the optic nerve at the back of the eye is assessed for any damage. A visual field test (peripheral vision test) is often performed along with an OCT (optical coherence tomography) scan which objectively measure any areas of damage to the optic nerve. These instruments are invaluable in providing baseline measurements for follow-up and help detect disease progression and hence, they’re often performed routinely at your eye specialist or optometrist reviews.

How do we treat glaucoma?

Treatment for glaucoma consists of medication such as eye drops, laser therapy or even surgery. The treatment will depend on the individual and the type & severity of the glaucoma. It is important to note that the aim of glaucoma treatment is to preserve the remaining vision. Damage from glaucoma cannot be reversed and thus, this chronic condition requires life-long review.

Medicated Eye Drops

The most common treatment option for glaucoma is the regular use of medicated eye drops. Some drops reduce the amount of fluid your eye produces, and others improve the way fluid drains from your eye. Our eye doctors can recommend the best drop or combination of drops for your specific circumstances.

Laser Therapy

In some cases, laser may be the first option to manage glaucoma. It can also be used in addition to eye drops and may be considered if the drops cause uncomfortable side effects. There are different types of laser used to treat glaucoma, such as:

  • Selective laser trabeculoplasty (SLT) is a special laser applied to the drainage system of the eye to improve the outflow of the fluid in the eye thereby, lowering the intraocular pressure. The laser is very safe and painless and can be a great alternative for patients who have trouble using eye drops. However more than one treatment is required for maximal effect and the efficacy of SLT may also reduce over time, so close monitoring is still required.
  • Laser peripheral iridotomy (LPI) is a treatment for angle closure glaucoma or as a preventative measure in patients who are at risk of angle closure glaucoma (narrow angles). A special lens is used to create a small hole in the peripheral iris (the coloured part of your eye). This improves the circulation of fluid inside the eye and allows for an alternative drainage pathway.

Minimally Invasive Glaucoma Surgery (MIGS)

MIGS are a new class of surgery that offers a safer, less invasive means for lowering intraocular pressure, that is most commonly combined with cataract surgery. The currently available MIGS implants are small microscopic titanium devices that are implanted inside the drainage angle of the eye. These stents and other similar devices cannot be seen or felt. They work by bypassing the blocked natural drainage system and allow the fluid circulating within the eye to drain out via a different route. There is minimal tissue trauma and disruption of the normal eye anatomy & physiology. Our eye specialists may suggest MIGS as an alternative treatment option especially for patients who are non-responsive to, or, have developed multiple sensitivities or allergies to commercially available glaucoma eye drops. The recovery from these procedures is quick compared to other types of surgeries. In many cases, MIGS can reduce or eliminate the use of medicated eye drops. It is important to note that these implants will not reverse any vision loss that has already occurred as a result of glaucoma but aim to slow down the progression.

Frequently Asked Questions

What are the symptoms of glaucoma?

Open-angle glaucoma usually does not significantly impair vision or cause other noticeable symptoms in the early stages. As it gets worse, it can cause the loss of peripheral (side) vision.

The symptoms of angle-closure glaucoma usually occur suddenly and can include severe eye pain, visible halos around lights, nausea, vomiting and blurry vision. If you experience any of the symptoms of angle-closure glaucoma, seek immediate medical attention.

How is glaucoma diagnosed?

Glaucoma is diagnosed through a comprehensive dilated eye exam and a review of your medical history. Our doctors measure your intraocular pressure and perform a visual field test to check for any areas of vision loss. Our doctors will also examine your optic nerve for any signs of damage.

What are the risk factors for glaucoma?

Glaucoma risk factors include the following:

  • Being over the age of 60
  • Being black, Asian or Hispanic
  • Having a family history of glaucoma
  • Having a pre-existing medical condition such as diabetes, heart disease or high blood pressure
  • Having a history of a traumatic eye injury
Can I stop glaucoma from progressing?

Appropriate medical or surgical intervention can prevent or slow the progression of glaucoma.

Depending on the circumstances of your case, our doctors may recommend lowering your intraocular pressure through the use of special medications or eye drops, laser treatment, traditional surgery or minimally invasive glaucoma surgery (MIGS). Sometimes two or more of these treatment options are combined.

Regular eye exams are crucial to monitor the progression of the disease.

Do glaucoma eye drops cause side effects?

Like any medication, some glaucoma eye drops are associated with mild side effects. These include stinging or red eyes, blurry vision, headaches and dry mouth. Usually these side effects are only temporary. If you experience persistent side effects, please let our doctors know.

Can I have glaucoma if my eye pressure levels are normal?

Yes, it is possible to have glaucoma with eye pressure levels that are average or even below average. These cases are known as “normal tension glaucoma.”

It is also possible to have higher than average eye pressure levels and not get glaucoma. If that is the case, you should be regularly monitored by our eye doctors to watch for any signs of damage to your optic nerve.

Is there a cure for glaucoma?

There is currently no cure for glaucoma, but the condition can be managed with the help of the right medical team. The earlier the disease is diagnosed, the better. Vision that has already been lost to glaucoma unfortunately cannot be restored.

For more information about the diagnosis or treatment of glaucoma, please contact The Eye Health Centre. We have four offices conveniently located in Brisbane, Booval, Aspley and Wynnum.

Do you have a question or concern about your eye health? To discuss your condition with an experienced ophthalmologist or optometrist, please contact The Eye Health Centre