Closed Angle Glaucoma

In contrast to Open Angle Glaucoma which is associated with a gradual increase in the intraocular pressure over time, Closed Angle Glaucoma is associated with sudden increase in pressure. The drainage angle can become partly or completely blocked by the iris, causing a sudden rise in intraocular pressure or acute angle-closure glaucoma attack.

A Closed Angle Glaucoma attack can cause severe ocular pain and redness, reduced vision, coloured haloes around lights, headache, nausea and vomiting. Early symptoms may include blurred vision, haloes around lights, headache, mild eye pain and redness. In contrast to open angle glaucoma which is associated with a gradual increase in the intraocular pressure over time, Closed Angle Glaucoma is associated with sudden increase in pressure. The drainage angle can become partly or completely blocked by the iris, causing a sudden rise in intraocular pressure or Acute Angle-Closure Glaucoma attack.

Often someone at risk of Angle Closure Glaucoma have no or few symptoms prior to an attack. Risk factors include increasing age, hyperopia (long-sightedness), and Asian or Inuit ethnicity. All of these risk factors are associated with narrower anterior chamber angles. If one eye has had an attack of angle-closure, the other eye is also at risk and may need treatment.

Anything that results in the iris dilating can contribute to an angle-closure attack, such as dim lighting, dilating eye drops or certain medications that can cause the pupil to dilate (such as some antihistamine/decongestant drops, cold medications or sleeping pills) may cause an acute angle-closure glaucoma attack.

An assessment for narrow anterior chamber angles, or for Angle-Closure Glaucoma may include the following tests:

* Vision
* Intraocular pressure
* Gonioscopy
(the use of a special contact lens with mirrors to assess the anterior chamber angle)
* Dilated examination of the retina and optic nerve

Patients who are at risk for developing Angle-Closure Glaucoma should have a Laser Peripheral Iridotomy. In this procedure laser is used to make a small hole in the iris, creating a new pathway for fluid drainage from the eye, so that the balance between fluid entering and fluid leaving the eye is restored. This procedure is usually well tolerated and safe, and the iris hole created is tiny (about the size of a pinhead) and usually hidden by the upper eyelid.

Acute Angle Closure creates intraocular pressures that can very quickly damage the optic nerve and cause permanent vision loss, so this is an ocular emergency. In this situation the pressure is reduced with the uses of topical eye drops as well as oral medication. When possible laser will be used to perform a peripheral iridotomy to prevent future angle closure attacks.

Laser Iridotomy also resolves narrow angles and in some patients may be an appropriate treatment option.

http://www.glaucoma.org.au/