Written by Ng Zhi Wei, Pharmacist

What is glaucoma?^1,2,3

Glaucoma is a chronic eye disease that damages the optic nerve and lead to vision loss and irreversible blindness.¹ The optic nerve connected our eyes to our brain so that we can see.  The eye is a globe that is filled with fluid. The amount of fluid within the eye is consistently maintained at a healthy level. When the eye’s drainage system becomes clogged with fluid, it can cause the pressure within the eye (also known as intraocular pressure or IOP) to rise thus damages the optic nerve and result in vision loss.

Glaucoma is the second leading cause of blindness worldwide.¹ There is no cure for glaucoma but blindness from glaucoma is preventable if treatment is instituted early.

Types of glaucoma^1,2,3,4

There are many different types of glaucoma, the two main types of glaucoma are primary open-angle glaucoma and angle-closure glaucoma.

Primary open-angle glaucoma is the most common type of glaucoma. In primary open-angle glaucoma (POAG), the drainage angle that leads to the trabecular meshwork looks normal, but aqueous fluid exits the eye too slowly.

Angle-closure glaucoma is a less common type of glaucoma where the drainage is too narrow or begins to close, impeding the normal outflow of aqueous humor. It can be either chronic (an anatomically narrow angle or temporary episodes of angle closures over time) or acute (the angle narrows or closes suddenly).

Other types of glaucoma are less common, like low-tension or normal tension glaucoma, congenital glaucoma and secondary glaucoma. In low-tension glaucoma optic nerve damage and vision loss occurs even though IOP remains normal. Low blood pressure may be a risk factor.

Whereas congenital glaucoma happened in children that are born with a defect in the drainage angle that prevents the aqueous fluid from exiting the eye normally. Usually there are obvious symptoms, such as cloudy corneas, light sensitivity and watery eyes.

Secondary glaucoma develops due to complications of certain medical conditions (including diabetes and high blood pressure) or because of other eye conditions (such as cataracts and uveitis), side effects of medications, or trauma to the eye.

Symptoms of glaucoma^1,2,3,5

Glaucoma has no symptoms in its early stages, it has no uncomfortable or painful symptoms and can only be detected during a comprehensive eye exam.³ The condition develops so slowly, and symptoms are gradual and often go unnoticed.

Vision loss is first evident peripherally (side vision)- especially the part of vision that’s closest to the nose, then moves centrally. As the disease progress, patients will start to notice they can’t see things off to the side anymore. Without treatment, glaucoma can eventually cause blindness. Therefore, it is important to perform regular check-ups with ophthalmologist and find out the disease at early stage.

Action to prevent^1,2,5

• If you are in a high-risk group, get a comprehensive dilated eye exam to catch glaucoma early and start treatment.
• Even if you are not in a high-risk group, getting a comprehensive dilated eye exam by the age of 40 can help catch glaucoma and other eye diseases early.
• Open-angle glaucoma does not have symptoms and is hereditary, encourage family members to get checked for glaucoma.
• Maintaining a healthy weight, controlling your blood pressure, being physically active, and avoiding smoking. Healthy lifestyle helps prevent type 2 diabetes and other chronic conditions.

What’s the treatment for glaucoma?^1,2,3,6

The aim of glaucoma treatment is to preserve maximal functional vision throughout a patient’s lifetime without sacrificing his/her quality of life (QoL) and at a sustainable cost.¹ IOP lowering can be achieved by either medication (usually eye drops), laser treatment, surgery or any combination of these modalities.

Its’s important to start treatment immediately once you are diagnosed with glaucoma. While it won’t undo any damage to your vision, treatment can stop it from getting worse. 

Medicines. Prescription eye drops are the most common treatment. They lower the pressure in your eye and prevent damage to your optic nerve. To achieve good results medications should be used regularly and uninterruptedly.

Laser treatment. To lower pressure in your eye, doctors will use lasers to help the fluid drain out of your eye. 

Surgery. If medicines and laser treatment don’t work, surgical intervention is necessary to create the drainage channel. There are several different types of surgery that can help the fluid drain out of your eye.

It is important to realize that glaucoma treatment by medication or surgery only control the disease and not cured. Complying to treatment regimens to make sure eye pressure remain under constant control is crucial to prevent glaucoma from getting worse. By understanding and managing glaucoma effectively, you will be able to continue to enjoy a happy and active life.

References:

1. Jelinar MN JMW, Azhany Y, Farrah J, et al. (2017) Clinical Practice Guidelines Management of Glaucoma (2nd Edition), Malaysia:
2. National Eye Institute (2019) At a Glance- Glaucoma. [online] Available at https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/glaucoma (Accessed: 10 February 2020).
3. Haruki A, Manuel A, Paul C, et al. (2008) Asia Pacific Glaucoma Guidelines. Singapore: SEAGIG.
4. Glaucoma Research Foundation (2017) Types of Glaucoma. [online] Available at https://www.glaucoma.org/glaucoma/types-of-glaucoma.php (Accessed: 10 February 2020)
5. Boyd K. McKinney JK. (2019) “Who is at Risk for Glaucoma?”. America: American Academy of Ophthalmology.
6. Weinreb RN, Ting Aung, Medeiros FA, et al. (2014) The pathophysiology and treatment of glaucoma, a review. US: JAMA.