What is the cause of glaucoma?

Glaucoma is due to damage to the optic nerve. As the disease progresses, there may be visual field defects, which means a loss of part of the usual field of vision. In many cases, the eye pressure is raised due to a build-up of fluid inside the eye. This fluid may be overproduced or inadequately drained. The exact reasons may or may not be identifiable, although some patients may be associated with certain risk factors.

A positive family history is also a risk factor for developing glaucoma. At risk individuals are advised to undergo screening for glaucoma, as recommended by your ophthalmologist.

What are the types of glaucoma?

(1) Open-angle vs closed-angle glaucoma
Open-angle glaucoma is when the drainage angle of the eye is still open. In angle-closure glaucoma, the drainage angle is narrowed or closed, limiting or preventing normal drainage of the aqueous fluid out of the eye, causing pressure to rise.

(2) Acute vs chronic glaucoma

In acute glaucoma, the drainage angle of the closes suddenly causing the pressure to rise suddenly and severely. The patient may have symptoms of blurring, eye pain, halos and glare, or even headache, nausea and vomiting. Acute angle-closure glaucoma is a medical emergency that requires urgent attention and treatment.

In chronic glaucoma, there is usually no or minimal eye pain or discomfort. Visual loss occurs over a prolonged period of time. This type of glaucoma is often more difficult to notice by the patient until there is significant visual loss.


(3) Normal tension glaucoma

The optic nerve becomes damaged, even when the eye pressure is within normal range. Doctors and scientists are still researching the exact causes of the condition. However, there are certain risk factors which may be controlled to decrease the risk of further damage to the optic nerve.

(4) Secondary glaucoma

Some causes of glaucoma are due to the presence of other diseases, which may be ocular or systemic. In these situations, management of both the primary cause, as well as the glaucoma, would be important. Your ophthalmologist will advise on the management plan in detail.


(5) Glaucoma in children 

Rarely, glaucoma can occur in children, which may present at birth, infancy, or as an older child. Should this unfortunately occur, this would need specialised care and long-term management.

What will happen if my ophthalmologist suspects glaucoma?

Your doctor will perform a detailed eye examination, which may include some or all of the following examinations and/or investigations:

  • Visual acuity
  • Intraocular pressure examination
  • Examination of your drainage angle (known as gonioscopy examination)
  • Examination of your optic discs
  • Visual field examination
  • Optical coherence tomography of the retinal nerve fibre layer
  • Central corneal thickness measurement
  • Optic disc photography (for monitoring)

If glaucoma is diagnosed, your ophthalmologist may advise one or a combination of the following, including pressure-lowering eye drops, laser procedures, and/or surgery. Your ophthalmologist will discuss and advise with you in detail.

What are the risk factors for glaucoma? Should I have screening for glaucoma?

Glaucoma has a tendency in recent years to affect patients in younger age groups. While the vision damaged by glaucoma cannot be cured, you should be attentive to your eyes health if you fall under the high-risk groups for glaucoma:

  • Positive family history of glaucoma
  • Racial risk (Asians, African, Hispanic heritage)
  • Older age, especially for age 40 or above
  • High myopia (near-sightedness) or high hyperopia (long-sightedness) with 600 or more degrees
  • Prolonged steroid use
  • With history of eye injury
  • Thin corneas
  • With problems of hyperlipidemia, hypertension, and high blood sugar

Discuss with your ophthalmologist about your risk of glaucoma. If risk factors are present, your ophthalmologist may arrange for further examinations or investigations.

Glaucoma is one of the common causes of permanent visual loss and blindness, both locally and worldwide. Diagnosing, monitoring and treating glaucoma requires a series of examination and investigations. Early detection and treatment of glaucoma will help stabilise the condition to decrease the risk of further progression. If you have any questions about your eye or treatment, discuss with your ophthalmologist. 

Last Updated: Sep 2019
Please note that all medical health articles featured on our website have been reviewed by Quality Healthcare doctors. The articles are for general information only and are not medical opinions nor should the contents be used to replace the need for personal consultation with a qualified health professional on the reader’s medical condition.