A B C D E F G H I J K L M N O P R S T U V W

GLAUCOMA : ACUTE

What is Acute Glaucoma ?

Acute glaucoma occurs when the internal fluid drainage system in the eye suddenly becomes blocked. This results in an abrupt rise in the pressure within the eye to a dangerously high level. The eye become painful with severe aching and the vision very blurred. The eye becomes red and the symptoms may be so severe as to cause nausea and vomiting. For some day before an acute attack, milder symptoms may occur called sub-acute angle closure glaucoma. Typically the symptoms are of seeing coloured halo's around lights at night and accompanied by some aching of the eye with mild blurring of vision.

How does Acute Glaucoma occur ?

This condition occurs in individuals who are long sighted and have therefore an eye that is smaller than average. The structures in the front of the eye are more "crowded" with less space for fluid of the circulating fluid of the eye to drain out of the eye.

Why does Acute Glaucoma occur ?

The condition tends to occur in the evening or dark conditions which induces the pupil to dilate. When the pupil is mid dilated in a smaller eye the fluid can become trapped behind the pupil resulting in a sudden rise in pressure. Certain drugs which affect the pupil, for example, Tricyclic antidepressants and certain antispasmodic drugs can induce an angle closure attack in susceptible individuals. The condition is much more common in the elderly population. The reason for this is that the crystalline lens continues to grow throughout life and in a smaller eye this results in the front compartment of the eye becoming more crowded as the lens increases in size.

Treatment Involved for Acute Glaucoma

Treatment is an emergency as the high pressure in the eye can result in complete loss of vision within 24-48 hours. The pressure must be reduced in the eye initially by reducing the amount of fluid produced by the eye. This involves generally injecting a drug called Acetazolamide into a vein in the arm. Drops also used to reduce the size of the pupil in an attempt to "break" the pupil block. Occasionally if this treatment is not effective an intravenous infusion of Mannitol is necessary. This tends to shrink the fluid from the eye to break the cycle of high pressure. The secondary treatment when the pressure is reduced is to make an opening in the iris to act as a "safety valve" to allow fluid to drain by an alternative route. The operation is generally done with a YAG laser which is undertaken usually with local anaesthetic via a contact lens. It is also necessary to do a similar procedure to the other eye, which will inevitably at risk of a similar attack if untreated. Very occasionally it is necessary to do a surgical operation rather than a laser operation.

After Treatment for Acute Glaucoma

The initial treatment is usually successful in reducing the pressure to a safe level. However there is often due to the angle closure attack some damage to the normal drainage angle and long term treatment with eye drops to reduce the pressure is often necessary. Occasionally an operation to permanently reduce the pressure by making a small fistula opening in the eye called a trabeculectomy is necessary.

If Acute Glaucoma is Left Untreated

This condition if untreated will inevitably result in complete loss of vision due to the very high pressure impeding the circulation within the eye.