Primary angle closure (acute) glaucoma
This is a closed angle type of glaucoma, i.e. the iris is found to be blocking the drainage of the eye through the trabecular meshwork. It is a primary glaucoma because there is no known cause relating to another condition, although the problem itself is clearly visible and related to the depth of the drainage angle of the eye (which is narrow).
It includes acute angle closure glaucoma (previously called acute glaucoma) and chronic angle closure glaucoma.
Acute primary angle closure (sometimes called ‘acute glaucoma’) develops when the drainage in the eye is blocked because the iris has come forward, causing the drainage angle to ‘close’ and the eye pressure to rise. If it isn’t treated straight away, and permanent damage occurs, the term primary angle closure glaucoma is used.
Chronic angle closure develops slowly, usually without symptoms, although the reason for the rise in pressure is similar. When damage to the nerve has occurred the term chronic primary angle closure glaucoma is used.
This sort of glaucoma is less common in Western countries and more often found in people of Asian origin. It may be acute (sudden onset) or chronic (slowly developing).
Other risk factors include:
Acute and chronic angle closure become much more common with increasing age. It is uncommon below the age of 40.
Women suffer from acute and chronic angle closure more frequently than men.
If you are of Asian origin you are more at risk of angle closure glaucoma than someone of European origin. It may also come on at a younger age and be more severe.
If you have glaucoma, your close relatives have an increased chance of developing the condition. You should advise members of your family to have regular eye checks by an optometrist (optician).
People with a high degree of long sight are more prone to angle closure glaucoma.
Acute primary angle closure tends to be very painful because the rise in pressure happens suddenly. Symptoms include seeing halos around light sources, a red eye, cloudy vision and, sometimes, sickness. It must be treated straight away and in most cases vision recovers completely.
Sometimes people experience a series of mild attacks of angle closure. These are called sub-acute attacks and often occur in the evening. Vision may seem misty, with coloured rings around white lights and there may be some discomfort and redness in the eye. If you have these symptoms, you should consult your optometrist without delay.
Chronic angle closure develops slowly, usually without symptoms.
If you experience any of the symptoms described for primary angle closure, you should seek immediate help from your GP who will refer you to an eye specialist urgently. The condition must be treated quickly. If you are delayed, then go to the Hospital Eye Service urgently.
If you experience mild attacks where the vision may seem misty, with coloured rings around white lights and there may be some discomfort and redness in the eye, you should consult your optometrist without delay.
Acute angle closure is initially treated with drops and an intravenous injection to lower the eye pressure. Once the pressure is lowered, a laser or surgical procedure is carried out in order to bypass the blockage in your eye’s drainage system and prevent a recurrence of the problem.
Normally the same procedure is also performed in the other eye, in order to prevent an attack of acute angle closure in that eye. These treatments are not painful and are usually carried out as an out-patient, although a short stay in hospital may occasionally be required.
If primary angle closure is diagnosed and treated without delay there may be an almost complete and permanent restoration of vision. However, any delay in addressing the problem may result in permanent damage to the affected eye.
Occasionally the pressure may remain raised and ongoing treatment will be required, as for POAG.
Chronic primary angle closure is treated in a similar way with drops to lower the pressure. In addition, laser treatment is often given to prevent further angle closure.
Are there other types of treatment?
Other treatments, such as tablets, laser therapy and surgery are available, either in place of, or in addition to, eye drops.