What is primary angle closure?
Glaucoma is a term that describes a group of eye conditions that affect vision. When the eye is functioning normally, fluid is produced inside the eye and is then drained away through the drainage channel. The balance between the production and drainage of the fluid creates a normal amount of pressure in the eye, which is needed for the eye to maintain its shape and function. If the fluid cannot drain away properly, the pressure in the eye rises. If the pressure is too high, the optic nerve at the back of the eye becomes damaged. The diagnosis of glaucoma is given when there is evidence of optic nerve damage.
The most common type of glaucoma is called primary open angle glaucoma. This is when the drainage channel (located between the iris and the cornea) is open. When the drainage channel closes, the iris moves forwards and against the cornea, blocking the pathway to the drainage channel and causing the pressure in the eye to rise. If this pressure remains high for a period of time, the optic nerve can be damaged, which then leads to primary angle closure glaucoma.
Some eyes have a shallow anterior chamber and narrow angle due to the iris and lens being close to the cornea. This is often found in people with smaller eyes or who are long-sighted (hypermetropic).
There are a number of conditions that are closely related to primary angle closure:
Primary angle closure suspect – This is when tests show that the drainage channel in your eye is narrow and is at high risk of closing up at any time. This is more common in people with smaller shaped eyes where the iris is naturally closer to the cornea.
Acute angle closure – Primary angle closure is usually painless and occasionally causes symptoms of mild headache. However, if the drainage channel suddenly closes and the pressure suddenly becomes very high, the signs and symptoms are usually severe. This is called acute angle closure.
Examination with a hand-held contact lens (gonioscopy) can reveal a narrow drainage channel that is at a risk of closing completely.
It is possible to experience an acute angle closure attack if you have been diagnosed with primary angle closure suspect or if you have primary angle closure and are waiting for treatment. It is therefore very important that you are aware of the signs and symptoms of an angle closure attack.
Symptoms include:
- intense pain of the eye
- sore or tender eye area
- headache
- redness of the eye
- blurred and reduced vision
- seeing coloured haloes around lights
If you are experiencing any of these symptoms, you should seek medical advice as soon as possible.
The two main treatment options are laser peripheral iridotomy and cataract extraction surgery.
In this procedure, a laser beam is used to create a small hole in the iris. This provides another route for the fluid to flow and pushes the iris backwards, in turn helping to open the drainage channel. For more information on this procedure, please click button.
The natural lens of the eye gradually increases in size with age and reduces the available space in front of the eye where the fluid has to drain out of. Removing the cataract or natural lens and replacing it with a new, thinner
artificial lens has a number of positive benefits to the eye.
- eliminates the risk of angle closure glaucoma and sight loss
- reduces eye pressure
- improves vision
- improves visual field performance
- makes any further glaucoma surgery that is required easier for the surgeon
If the pressure in the eye remains high, extensive damage can occur to the optic nerve. This will lead to significant and permanent visual loss.