What are the different types of Glaucoma and the symptoms?

1. Open Angle Glaucoma (POAG) – Representing the most common form of glaucoma, POAG occurs when the aqueous drainage fluid canals are obstructed over time. Eye pressure gradually increases over a long period of time and because this buildup occurs at such a slow rate, patients are unlikely to notice their peripheral vision decreasing or having patchy blind spots. There are no symptoms present in the early stages. Difficulty to see things within the central vision only occurs at a later stage.
2. Acute Closure Glaucoma (ACG) – Contrasting to POAG, angle closure glaucoma happens very rapidly and represents an emergency case. The angle between the cornea and the iris becomes too narrow, blocking sufficient drainage of fluid. Patients will experience sudden blurring of their vision, eye pain, nausea and vomiting, headache, eye redness and may see halos or coloured rings around bright lights.
3. Normal Tension Glaucoma (NTG) – NTG is when there is damage to the optic nerve despite eye pressure remaining in the normal range. The optic nerve may be sensitive or have less blood flow. People who have NTG will not notice any symptoms in the early stages but gradual progression can lead to loss of side vision in the later stages. The exact reason for NTG is still unknown.
4. Secondary Glaucoma – Eye injury, inflammation, infections or advanced stages of cataracts and diabetes are possible causes of secondary glaucoma. Long-term usage of some medication such as steroids can also cause secondary glaucoma.
5. Congenital Glaucoma – This form of glaucoma is diagnosed during infancy or early childhood. This may be due to a hereditary defect or an abnormal development during pregnancy. Children with congenital glaucoma will show signs of a cloudy, white and enlarged protruding eye, have excessive tearing and are sensitive to light.

How is Glaucoma detected?

At Eyecentric at Bukit Tinggi Medical Centre, our trained eye specialists and ophthalmologists will conduct comprehensive eye exams to correctly diagnose if you have a case of glaucoma. These tests include:

• Dilated eye examination – The doctor will administer dilating drops to open your pupil, making it easier to examine your optic nerve.
• Tonometry – A specialised instrument called a tonometer is used to measure the pressure within your eyes. Anesthetic eye drops and dye will also be used. The next step is for a small probe to be placed against the surface of the eye to measure the eye pressure.
• Gonioscopy – The ophthalmologist will use a special lens to examine the structure inside the eye, particularly the drainage angle.
• Corneal thickness assessment – The thickness of the cornea can affect the accuracy of the eye pressure measurement. Thicker corneas may falsely indicate higher pressures while thinner corneas may falsely indicate lower pressures.
• Optical Coherence Tomography – The optic nerve and internal structures are examined through the use of a sophisticated non-invasive imaging technology.
• Visual Field Test – This test requires the patient to stare straight into a machine and click a button on a remote to signal your ability to notice a blinking light in your peripheral vision.

What are the treatments for Glaucoma?

• Eye drops are usually the first line of treatment. Different types of eye drops may be used to promote drainage of fluid in the eye or reduce the production of fluid in the eye.
• Pills may also be prescribed if eye drops fail to relieve eye pressure
• Laser Peripheral Iridotomy (PLI) – Used to facilitate the flow of fluid in an eye with narrow angle
• Argon Laser Trabeculoplasty and Selective laser Trabeculoplasty – Performed in cases of Open Angle Glaucoma, where the eye’s drainage system is altered to enable eye fluid to drain out easily
• Trabeculectomy – The eye doctor creates a passage in the white part of the eye to drain excess eye fluid
• Drainage Implant Surgery – Small silicone tubes is inserted into the anterior chamber of the eye to aid in fluid drainage