What is Glaucoma?
Glaucoma is a common but poorly understood eye condition that has the potential to cause significant loss of vision. It is essentially an optic (eye) nerve disorder characterised by progressive loss of nerve fibres and peripheral visual field in the earlier stages followed by loss of central vision in advanced stages.
There are two major types of glaucoma: Open angle glaucoma and closed angle glaucoma. The former and subtypes of the latter do not cause any symptoms that may prompt the patient to seek consultation with an eye doctor. Late presentation may result in devastating visual field loss that is irreversible. For this reason, glaucoma is often called “the silent thief of sight”.
The following link to the American Academy of Ophthalmology page on glaucoma gives a good synopsis of the two main types of glaucoma: https://www.aao.org/eye-health/diseases/what-is-glaucoma
What are the signs and symptoms of Glaucoma?
For open angle glaucoma, there are often no symptoms. It is only with eye screening that eye doctors are able to pick up the signs that raise suspicion of the condition. These include raised intraocular pressure and/or a suspicious appearance of the optic nerve head.
Specialised eye clinic tests including visual field testing and tests that determine the thickness of the retinal nerve fibre layer around the optic nerve head are then performed to determine if the patient indeed has glaucoma. If tests fall within the normal range, the patient will require further monitoring over time to ensure there is no progression.
For these patients, some will continue to have normal test results and no treatment is required. In others, tests may confirm the development of glaucoma and treatment will be required.
For closed angle glaucoma, there are two main subtypes: acute and chronic. Patients with acute closed angle glaucoma will present with eye pain, eye redness, blurred vision, nausea, vomiting and headache. They often have to rush to see an eye doctor or to the emergency department for urgent medical attention to avoid devastating loss of vision.
For chronic closed angle glaucoma, patients do not experience intense pain but may instead report a more vague eye discomfort and seeing halos around lights intermittently. Frequently, like open angle glaucoma, the condition can be asymptomatic.
Who is most at risk of developing Glaucoma?
Risk factors for developing glaucoma include a positive family history, high myopia and a history of migraine. Glaucoma can also result secondarily from use of steroid eye medication, previous eye trauma, inflammation, severe diabetic eye disease or other retinal blood vessel disease that restrict oxygen flow to the retina.
Is Glaucoma hereditary?
The genetics underlying glaucoma are complex and still not fully understood. Fortunately, a positive family history does not always mean that one will inherit the disease although the risk is higher compared to the general population. Genetic testing is not recommended unless the condition is seen as part of a syndrome.
How often should you check for Glaucoma?
The American Academy of Ophthalmology recommends eye screening at 40 years of age. Following that, our clinic recommends a review every one to three years depending on the clinical findings. Once a patient reaches 65 years of age, the AAO recommends yearly eye examinations as the chances of detecting eye disease is higher with increasing age.
What are the different treatments for Glaucoma?
Treatments can be categorised into 3 groups:
- Medical treatment
- The vast majority can be treated with glaucoma eyedrop medications. There are several types with different mechanisms of action. Your eye doctor will help you start on a suitable medication or a combination of medications that can help control the eye pressure and avoid disease progression
- Laser treatment
- Laser treatments include argon laser trabeculoplasty and laser peripheral iridotomy for open and closed angle glaucoma respectively
- Surgical treatment
- Surgery ranges from canaloplasty to standard trabeculectomy and in more severe cases, to the use of glaucoma drainage implants
Is Glaucoma related to blood pressure?
High eye pressures have been found to be associated with high blood pressure in population-based studies. Therefore, if one has high blood pressure, controlling it well could help reduce the eye pressure somewhat. However, the degree to which it can help will vary from patient to patient.
On the other hand, if blood pressure is lowered too much, diminished blood supply to the optic nerve head could be detrimental as well. A fine balance is crucial to optimise the health of the optic nerve.
When should you consider Glaucoma surgery?
This crucial step can be considered if the condition cannot be controlled adequately with combination glaucoma eyedrop medications alone. In other words, when the patient’s eye pressure remains higher than target level and/ or tests show worsening even with the use of multiple glaucoma medications.
Is there a chance that Glaucoma can be cured?
It is not possible to say that glaucoma can be cured. The more appropriate and correct statement that can be made is that with the right treatment, glaucoma can be managed and controlled optimally to minimise further visual field or central visual loss so that one never completely loses vision within one’s lifetime.