Glaucoma

What is Glaucoma?

Glaucoma is a progressive eye condition where there is irreversible damage to the optic nerve. The optic nerve is located in the back of the eye and is also known as the cranial nerve. It's role is to transfer visual information from the retina to the brain.

Glaucoma often develops when intraocular pressure (IOP) becomes abnormally high, though it can also occur with normal eye pressure (a condition called normal-tension glaucoma). The shape of the eye is maintained by intraocular pressure. If the pressure becomes too high, the fibres in the optic nerve are at risk of damage. No noticeable symptoms are presented in the early stages of glaucoma.

Symptoms may start so slowly that you may not notice them. If left untreated, it causes varying degrees of vision problems that can eventually lead to total blindness. It is one of the causes of blindness among the elderly, and early detection is vital to slow down or prevent vision loss. Glaucoma can affect anyone but it is more common in older adults.

What are the types of Glaucoma?

The different types of Glaucoma includes:

• Open-angle Glaucoma: The most common type of Glaucoma, open-angle Glaucoma and is characterised by increased intraocular pressure, potentially leading to optic nerve damage and vision loss. While IOP is often elevated, damage can also occur even when pressure is within the normal range.
• Acute angle-closure Glaucoma: This serious condition happens when fluid in your eyes can't drain the way it should, leading to a sudden or rapid buildup of pressure inside the eye, called Intraocular Pressure (IOP).
• Congenital Glaucoma: Congenital Glaucoma affects approximately one in 10,000 babies. Children with congenital Glaucoma will usually have noticeable signs such as cloudy eyes, eyes that are larger than normal and photosensitivity in the children.
• Secondary Glaucoma: This condition refers to any form of Glaucoma where there is an identifiable cause of increased eye pressure, resulting in optic nerve damage and vision loss.

What are the symptoms of Glaucoma?

Your symptoms will depend on the type of Glaucoma you have. Symptoms include:

• Blurred vision
• Eye pain
• Eye redness
• Halos around lights
• Nausea and vomiting
• Severe headache
• Difficulty seeing things in your central vision
• Gradual loss of vision

In open-angle glaucoma, symptoms are usually absent until significant vision loss occurs. In acute angle-closure glaucoma, symptoms may include eye pain, redness, halos around lights, headache, nausea, and vomiting.

What causes Glaucoma?

Glaucoma develops when the optic nerve becomes damaged. As the nerve damage worsens, blind spots develop in your vision. Optic nerve damage is usually related to increased pressure in the eye that happens as a result of a buildup of fluid that flows inside the eye.

This fluid, also called the aqueous humor, typically drains where the iris and cornea meet. However, when the eye produces too much fluid or the drainage system does not work properly, eye pressure may increase.

How do you prevent Glaucoma?

Early detection of glaucoma may help to prevent vision loss or slow its progression. Here are steps to help you detect it early and manage glaucoma in its early stage. 

• Regular eye examinations: Regular eye exams can help to find glaucoma in its early stages, before more damage occurs. If you are at risk of glaucoma, you'll need screening more often. 
• Be aware of your family's eye health history: Glaucoma tends to run in the family, if you are at an increased risk of glaucoma, you may need more screenings. 
• Wear eye protection: Serious eye injuries may lead to glaucoma. Consider wearing eye protection when using power tools or playing sports. 
• Take prescribed eye drops regularly:  Glaucoma eye drops can greatly reduce the risk that high eye pressure will progress to glaucoma.

What are the risk factors of Glaucoma?

Factors that can increase your risk of developing Glaucoma include:

• High intraocular pressure
• Being age 50 and older
• A family history of Glaucoma
• Pre-existing medical condition such as diabetes, migraines, high blood pressure, and sickle cell anemia
• Extreme nearsightedness and farsightedness
• Eye injury

How is Glaucoma diagnosed?

Eye exam
Several eye exam tests may be carried out to measure eye pressure and corneal thickness, optic nerve damage and vision loss. Some of these tests may include:

• Tonometry (measuring intraocular pressure)

• Ophthalmoscopy (examining the optic nerve)

• Perimetry (visual field test)

• Pachymetry (measuring corneal thickness)

• Gonioscopy (examining the drainage angle of the eye)