Acute angle-closure glaucoma treatment

Treatment for acute ACG usually begins with topical eye drops and intravenous medication, both which aim to reduce IOP and provide pain relief. The eye drops narrow the pupil, which lowers the amount of fluid your eye makes and helps to decrease pressure. Once the IOP has reduced a little, your ophthalmologist may discuss with you surgical options for further treatment if necessary.

These are common medication types and treatments an ophtamologist might recommend for acute angle-closure treatment.

Carbonic anhydrase inhibitors (Acetazolamide)

If someone with acute ACG has an extremely high IOP, Diamox tablets (a common brand of Acetazolamide) is immediately administered.

Acetazolamide is a diuretic (designed to expel water from the body) and its purpose is to decrease fluid build-up in the eye, consequently controlling the rapidly rising IOP. It may also be prescribed for a certain period of time to keep the pressure in control.¹

Mannitol

Unless the patient has a contradicting health condition, such as kidney disease or dehydration, a Mannitol injection can be given intravenously to reduce the pressure. This diuretic works by decreasing vitreous volume (a clear, colourless fluid that fills the space between the lens and the retina) which ultimately prevents further build-up of IOP.

Since these have a number of potentially serious side effects and are typically used only in acute situations, they will usually be used in hospital under careful monitoring.²

Osmotic agents

Osmotic agents are types of diuretics that restrict the absorption of water and sodium.

Hyperosmotic agents such as sodium chloride, glycerine or isosorbide can be given topically (such as an eye drop) or taken orally as a pill to help clear corneal swelling (swelling of the clear, protective outer layer of your eye) and bring down a severely high IOP.

A hyperosmotic agent does this by releasing a large dose of a sugar-like chemical into the bloodstream, which inhibits water absorption. This thins the water content in your blood. To compensate for this, the eye will transfer excess water into blood vessels within the choroid and retina. It’s this action that can help relieve IOP.

However, these medications can have some side effects. These can range from headaches, nausea and vomiting to pulmonary oedema and congestive heart failure, especially in diabetic and hypertensive patients.³ Therefore, Mannitol remains the preferred method of intravenous treatment.

Steroids

Steroids like prednisolone are often used in limited doses to reduce inflammation and pain.⁴ These are used sparingly, as steroids have been known to increase IOP.

In most cases of ACG, Iridotomy (a laser procedure) is considered the most effective treatment option. As such, the medications listed above would generally be used to help prepare the eye for laser peripheral iridotomy.⁵

Laser peripheral iridotomy

When the angle is partially or completely closed up, a laser is used to make small holes in the peripheral area of the iris, to assist drainage of fluid.

Your ophthalmologist may also recommend that the procedure be performed in the other eye, as a pre-emptive measure.

Paracentesis

Manual drainage (paracentesis) of eye fluid is usually only performed as a final measure to bring down IOP until the medication starts to take effect. It’s not really a preferred route to take, however, due to the potential complications it can lead to, such as permanent damage to ocular structures and eye fluid inflammation (endophthalmitis).⁶

Treatments for chronic angle-closure glaucoma

Miotics

Angle-closure glaucoma can occur if your pupil dilates too much or too quickly. A common symptom before the onset of acute ACG can be eye pain in the evenings, when watching television or reading in low level lighting for example.

Miotic eye drops work to reduce eye pressure by increasing the drainage of the aqueous humour through the trabecular meshwork (an area of tissue responsible for draining the aqueous humour from the eye via the anterior chamber). It does this, essentially, by constricting the pupil. This constriction exerts a ‘pull’ on the trabecular meshwork, which helps to increase the flow of eye fluid. As a result, it can reduce IOP.⁷

Beta-blockers

Used in a variety of glaucoma eye drops, this medication decreases the aqueous humour production in the eye and so reduces the rate at which the fluid flows into the eye. This can then lead to a drop in the IOP.⁸

Cataract removal

The formation of cataracts can cause the eye lens to thicken. As this continues, it can push the iris forward and, as a result, can cause the narrowing of drainage channels. Removing the lens and replacing it with a thinner intraocular lens can naturally open up the angle.

To understand more about the link between glaucoma and cataracts, you can find an in-depth article here.

Filtration surgery

While primarily used for the treatment of open-angle glaucoma, filtration surgery can be performed for either type of angle-closure glaucoma. However, this would usually only happen if laser facilities are unavailable, and if damage to the optic nerve is significant.

Learning about glaucoma treatment can be a little overwhelming and difficult to understand. So, we’ve developed a glaucoma resource designed to help you to develop a thorough understanding of glaucoma as a whole – from glaucoma causes to glaucoma diagnosis to glaucoma treatment.