What is Glaucoma and How is It Managed? All You Need to Know

Glaucoma is not an uncommon disease. In fact, it’s probably a lot more common than we realise. Statistics tell us that about 50% of people don’t even know they have it. Keep reading to find out more about what is glaucoma, how to know if you’re developing glaucoma and the options for glaucoma treatment. 

What is Glaucoma?

Glaucoma is a disease of the optic nerve. Because the optic nerve is crucial for carrying neural signals from the eyeball to the visual areas of the brain, if enough of these nerve fibres become damaged, it will result in slow and progressive vision loss. This vision loss typically starts in the periphery of your sight. 

In many cases, glaucoma is associated with high eye pressure, commonly called intraocular pressure. However, the association between developing glaucoma and elevated intraocular pressures is not always straightforward. You may have intraocular pressures outside of the normal range but still have no evidence of glaucoma or optic nerve damage. Such cases may be termed ocular hypertension. Conversely, someone with intraocular pressures that are considered to be within normal may still show signs of vision loss from optic nerve disease. This is a type of glaucoma known as normotension or low-tension glaucoma. Glaucoma may also be categorised into an open angle (there is sufficient space between the iris and the cornea, where fluid drains from the eye) or a closed angle (this space is compromised). 

What is Glaucoma Caused By?

At the moment, experts don’t fully understand what causes glaucoma or why someone’s intraocular pressure might start increasing. We know that intraocular pressure is influenced by the balance of aqueous fluid production and drainage. If aqueous is unable to drain from the eye at the same rate as it is produced, the pressure inside the fixed volume of the eyeball will increase. If this high intraocular pressure persists, it can end up damaging the optic nerve and causing glaucoma. 

While we don’t always have an explanation as to why there may be an imbalance between aqueous production and drainage, some situations have a more obvious cause. 

• Trauma to the eye can damage the fluid drainage structures
• Anatomical anomalies to the eyeball may result in a poorly formed drainage structure, such as congenital malformations
• Changes to the relationship of anatomical structures inside the eye over time. For example, if a cataract develops, it can cause the lens to push the iris toward the cornea, which subsequently narrows the space around the drainage channels
• Free-floating debris or pigment cells in the eye clog up the drainage channels

There are also a number of factors associated with a higher risk of developing glaucoma. You may have none of these risk factors but still, end up developing glaucoma. Conversely, you may have all these factors and never show evidence of glaucoma.

• Elevated intraocular pressures
• Older age
• Asian, African American, or Hispanic ethnicity
• Family history of glaucoma
• Corneas that are thinner than average
• High degrees of short- or far-sightedness
• The use of corticosteroid medications
• Diabetes
• Migraines or obstructive sleep apnoea

How is Glaucoma Diagnosed and Treated?

Glaucoma is almost always diagnosed during a routine eye test. In the vast majority of cases, the disease demonstrates no symptoms, leading doctors to nickname it the “sneak thief of sight”. One type of glaucoma, known as acute angle closure glaucoma, may present with a painful, red eye, vomiting, and visual disturbances (though it is not unknown for people to mistake what is actually glaucoma for a stomach bug). 

Your optometrist or ophthalmologist may suspect you have glaucoma during a regular eye exam due to high intraocular pressures or an unusual appearance of your optic nerve. Further assessment with visual field testing (testing the sensitivity of your peripheral vision) and optical coherence tomography (a measurement of your nerve fibre layer and associated optic nerve or macular analyses) can help to confirm the diagnosis. However, glaucoma is often slowly progressive, so your eyecare practitioner may need more than one test result over time in order to have a clear diagnosis.

If you are found to have glaucoma, your eyecare practitioner will discuss glaucoma treatment options with you. Glaucoma treatment is always aimed at lowering the intraocular pressure in order to protect the optic nerve. Traditionally, first-line treatment has been in the form of prescription eye drops. There are a number of different medications, and some need to be used up to three times a day. You may also need multiple types of drops to control the intraocular pressure. 

If medications are found to be ineffective or if you find it difficult to follow the dosing regime, your ophthalmologist may escalate your glaucoma treatment and recommend a laser procedure or surgery. One of the most commonly used laser procedures is known as selective trabeculoplasty. This involves using a laser to stimulate the removal of any debris blocking the drainage channels.

For closed-angle glaucoma, a laser can be used to create a hole in the iris, which aids the drainage of aqueous. Surgery is usually considered a last resort if intraocular pressure can’t be sufficiently controlled with other methods. The various surgical procedures aim to improve the drainage of fluid from the eye.

Since glaucoma typically doesn’t present with any obvious symptoms, it’s important to maintain regular eye tests with your eyecare professionals. This is especially true if you have any risk factors for glaucoma, including being aged over 50.

Call us on (03) 9070 3580 today.

Note: Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.

References

What is Glaucoma?
https://glaucoma.org.au/what-is-glaucoma#:~:text=What%20causes%20glaucoma%3F,optic%20nerve%20varies%20between%20people.

The Pathophysiology and Treatment of Glaucoma.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4523637/#:~:text=Primary%20closed%2Dangle%20glaucoma%20is,anterior%20chambers%20at%20the%20pupil.

Glaucoma.
https://www.mayoclinic.org/diseases-conditions/glaucoma/symptoms-causes/syc-20372839