CAUSE & SYMPTOMS

Primary angle closure glaucoma (‘’narrow or closed angle glaucoma’’) is the less common of the two major types of glaucoma where in the iris tends to be blocking the filtration channels (trabecular meshwork) of the eye resulting in obstruction of the drainage of fluid out of the eye. This can lead to a sudden sharp rise of eye pressure resulting in ‘an attack of angle closure’ which may give rise to the following symptoms :

• red eye
• severe eye pain (or headache)
• seeing haloes around lights
• cloudy vision
• sickness

Sometimes patients might experience intermittent ‘sub-acute attacks’ classically in the evening giving rise to misty vision, coloured rings around white lights  and some discomfort around eyes. The rise of pressure can also happen over a longer period of time when these acute symptoms are lacking (‘chronic angle closure’).

Field loss in patient with advanced glaucoma

RISK FACTORS

• Patients above 40 years of age
• Long-sightedness (high plus power in spectacles)
• Ethnic origin – commoner in Asians (rarer in Caucasians)
• Females

Many drugs can cause angle closure, including drugs with "anti-cholinergic" side effects. For such medications, there is usually a caution on the enclosed medication leaflet that advises "do not take this medication if you have glaucoma". Other drugs that can cause angle closure include sulpha based drugs (eg topiramate), dilating drops (eg cyclopentolate) and some anti-depressant medications (eg amitriptylline).

DIAGNOSIS

If patients experience any of the above symptoms they should contact their GP or optician immediately so that they can be referred to the hospital eye clinic for urgent treatment to avoid permanent loss of sight.

TREATMENT

Patients usually require admission for treatment of acute angle closure glaucoma. The treatment is with tablets or intravenous injections to reduce the eye pressure rapidly along with lots of eye drops. It may take from a couple up to few hours before the eye feels comfortable and the pressure is adequately lowered. Once the pressure in controlled, patients often require a further laser treatment (YAG laser iridotomy) in the affected eye to prevent a future recurrence and often a preventative laser treatment in the other good eye which carries the risk of a similar attack. Often many of these patients will go on to have a cataract extraction operation in near future which is best decided by the glaucoma specialist.

Narrow angles demonstrated on OCT