Glaucoma is a disease of the eye that causes damage to the optic nerve. The optic nerve is the pathway that carries the images we see to the brain. The disease can destroy the optic nerve leading to blindness, if left untreated. Based on National Eye Survey 2014, galucoma is the third most common cause of blindness in Malaysia (1%) after cataract (58%) and diabetes (10%).
Glaucoma can affect anyone. However, certain factors associated with higher risk, which include:
- Age: risk increases with increasing age
- Race: African and Chinese ancestry
- Family history of glaucoma
- Pressure in the eyeball. People with pressure more than 22 mmHg ( ocular hypertension)
- Short sighted (myopia)
- High blood pressure / Hypertension
- Diabetes Mellitus
- Prolonged use of steroid drugs (either topical or systemic)
Types Of Glaucoma
Glaucoma can be divided into 2 types. These are:
- Closed angle glaucoma
- Open angle glaucoma
Signs and Symptoms
Signs and symptoms of glaucoma depend on the type of glaucoma.
A. Closed angle glaucoma
- Eye pain
- Blurring of vision in the affected eye
- Eye redness
- Nausea and vomiting
- Increased intraocular pressure (IOP)
This is due to very high pressures in the eyeball resulting from blockage in the drainage system of the eye. Most patients at risk for this type of glaucoma have structural differences in their eye which could be identified by eye doctor prior to an attack and preventive treatment could be performed to prevent attack.
B. Open angle glaucoma
This type of glaucoma may present with painless and slow progressive loss of vision that may escape detection by the patient. Thus, this stresses the importance of eye screening, especially in patients with a family history of glaucoma
- Usually no symptom till disease is severe
- Progressive loss of vision
- Narrowing of visual field
- Increased intraocular pressure (IOP)
- Increase cup disc ratio (indicating chronic damage of the optic nerve)
Important Tests For Glaucoma
- Vision test
- Measurement of intraocular pressure (pressure of eyeball)
- Visual field test
- Evaluation of optic nerve by funduscopy
What Is Visual Field
It is the area that can be seen by the eye. It is measured by using a specific equipment and the graft produced is used to make a diagnosis as well as monitoring the progress of the disease. The frequency of the test depends on the severity and the rate of progress of the disease.
|Equipment used for visual field testing||Chart showing visual field defect|
What Is Intraocular Pressure (Eyeball Pressure)
It is the amount of pressure exerted from within the eyeball in order to maintain the integrity of the eyeball. Normal pressure is between 10-20 mmHg. It is measured by using a devise called tonometer. IOP is measured at every visit to monitor the control of the disease. Some center might use a non-contact devices (eg. Air puff tonometer) which give almost similar reading.
|Photograph showing IOP measurement||Examples of tonometer|
Evaluation Of Optic Nerve
At every visit, an eye doctor will evaluate the appearance of optic nerve head by doing funduscopy. This is to see the progression of optic nerve damage due to glaucoma.
|Optic nerve in eye with glaucoma|
Without proper treatment, glaucoma damages the optic nerve. The patient’s visual field can shrink leading to tunnel vision or even loss of vision. Ultimately, glaucoma can cause irreversible blindness.
The primary goal of treatment is to preserve vision. There are various form of treatment which includes medication, laser and ultimately surgery. Treatments help in lowering the eyeball pressure by helping fluid leave the eye or by reducing the amount of fluid produced in the eye.
2. Laser treatment
Laser treatments can be given for both angle closure and open angle glaucoma. Laser treatment for angle closure glaucoma is usually performed to prevent an acute attack by creating hole in the iris to facilitate drainage system in the eye. In open angle glaucoma, laser is performed when medications are not effective enough or the patient has difficulty in taking medications.
The procedure involves making an alternative drainage system for the fluid in the eye to escape from the eyeball. It is usually performed when medications and lasers are ineffective.
To date, with proper medical care, glaucoma may be treated and controlled. Since most people with glaucoma experience no noticeable symptoms, especially in open angle glaucoma, an eye examination for glaucoma, including specialized testing, is the most important tool in preventing vision loss from the disease.
|Last Reviewed||:||23 August 2019|
|Writer/Translator||:||Dr. Salmah bt. Othman|
|Accreditor||:||Dr. Hjh. Nor Fariza bt. Ngah|
|Reviewer||:||Dr. Rosniza bt. Ab. Razak|