When the iris blocks the drainage angle, the eye pressure rises, this can happen gradually or suddenly. Treatment with Laser Peripheral Iridotomy is effective in most cases.
Acute Angle Closure Glaucoma
If the drainage angle becomes completely blocked, the eye pressure rises and if this happens suddenly, it is called an acute angle closure attack.
Acute angle closure glaucoma is a serious eye emergency, and you should look for the following symptoms:
- sudden onset of blurred vision
- severe eye pain and red eye
- headache
- nausea
- vomit
- rainbow – colored rings or halos around lights
Chronic Angle-closure Glaucoma
Angle-closure glaucoma can develop slowly without causing symptoms for many years, or causing only infrequent “attacks” of mild acute symptoms. This is called chronic angle-closure glaucoma. About 1 in 3 of people with chronic angle-closure will have a sudden blockage, causing an attack.
Risk factors include:
- a lens that is too large (keeping fluid from flowing normally through the pupil)
- a small (shorter than average) eye
- a combination of the above
- an iris that is thicker than normal
- an iris with a roll on the edge that can block fluid (called “plateau iris”)
Actually, as we get older, our natural lens grows bigger and causes a small degree of angle closure in a significant number of “open angle” glaucoma patients.
Chronic Angle-closure Glaucoma
Angle-closure glaucoma can develop slowly without causing symptoms for many years, or causing only infrequent “attacks” of mild acute symptoms. This is called chronic angle-closure glaucoma. About 1 in 3 of people with chronic angle-closure will have a sudden blockage, causing an attack.
Risk factors include:
- a lens that is too large (keeping fluid from flowing normally through the pupil)
- a small (shorter than average) eye
- a combination of the above
- an iris that is thicker than normal
- an iris with a roll on the edge that can block fluid (called “plateau iris”)
Actually, as we get older, our natural lens grows bigger and causes a small degree of angle closure in a significant number of “open angle” glaucoma patients.
How is it Diagnosed?
The only way to diagnose chronic angle-closure glaucoma is with a complete eye exam. An eye pressure measurement on its own is not enough to diagnose the condition.
The definitive examination that will confirm the diagnosis is called “gonioscopy”. This might be slightly uncomfortable but not painful, as anaesthetic drops are instilled in the eye. it involves holding a special contact lens on the eye, which allows me to evaluate the drainage system of the eye. This only takes a few minutes per eye. Obviously, the same tests as in open angle glaucoma are done, i.e. visual fields, OCT and corneal thickness.
Treatment
As in open angle glaucoma, any damage on the optic nerve is irreversible. But with the appropriate treatment, we can stop the progression of the disease. In most cases, laser or surgery is required to reopen the blocked drainage angle. Some drops are also used to help the control of the eye pressure.
Laser Peripheral Iridotomy
I use a laser to create a tiny hole in the iris. This hole helps fluid flow to the drainage angle. Please refer to the video.
Surgery
In many cases there is a thick lens in a smaller than average eye, therefore removing the natural lens and replacing it with a clear one helps to ‘open’ the angle. Some clinicians say that the most common glaucoma operation is in fact cataract extraction. A replacement lens implant is placed in the eye, which improves the vision and also lowers the risk of glaucoma progression.
A recent international multicentre study showed that cataract surgery with lens replacement is effective for angle closure glaucoma even when there is hardly any cataract present in people with high eye pressures due to angle closure glaucoma.
In some cases where laser or cataract surgery is not effective in lowering the eye pressure, more specialised glaucoma filtration surgery such as trabeculectomy or even tube surgery might be required.
Surgery
In many cases there is a thick lens in a smaller than average eye, therefore removing the natural lens and replacing it with a clear one helps to ‘open’ the angle. Some clinicians say that the most common glaucoma operation is in fact cataract extraction. A replacement lens implant is placed in the eye, which improves the vision and also lowers the risk of glaucoma progression.
A recent international multicentre study showed that cataract surgery with lens replacement is effective for angle closure glaucoma even when there is hardly any cataract present in people with high eye pressures due to angle closure glaucoma.
In some cases where laser or cataract surgery is not effective in lowering the eye pressure, more specialised glaucoma filtration surgery such as trabeculectomy or even tube surgery might be required.