Closed-Angle Glaucoma¹¹ Yanoff M, Duker JS. Ophthalmology. 1st ed. London, UK: Mosby International Ltd; 1999

Closed-angle glaucoma affects nearly half a million people in the United States. This disease is often inherited, with several members of a family afflicted. It's most common in people of Asian or Inuit (Eskimo) descent and those who are far-sighted.

In closed-angle glaucoma, the anterior chamber is shallower than average. Over time, the angle between the iris and the cornea becomes narrower. Eventually, the iris is forced against the trabecular meshwork drainage system, preventing aqueous humor from draining through. When this space becomes completely blocked, a closed-angle glaucoma attack (acute glaucoma) results.

Acute Closed-Angle Glaucoma
An acute closed-angle glaucoma attack can occur in a matter of hours. Symptoms may include:

• Red eye
• Swollen and cloudy cornea
• Blurred vision or flashes of light
• Pain (enough to sometimes cause nausea and vomiting)

An acute closed-angle glaucoma attack is an emergency.
If treatment is delayed, eyesight may be permanently destroyed, or the trabecular meshwork drainage system may become scarred, resulting in chronic closed-angle glaucoma, which is much more difficult to control. Cataracts or damage to the optic nerve may also develop, causing permanent damage to vision.

Triggers of attacks.
Many of these sudden “attacks” occur in darkened rooms, such as movie theaters. That's because as the pupil dilates to bring in more light, it further narrows the angle of the anterior chamber, blocking the flow of fluid.

The pupil also dilates during times of excitement or anxiety. Consequently, many acute closed-angle glaucoma attacks occur during periods of stress.

A variety of drugs can also cause the pupil to dilate and lead to an attack, including antidepressants, cold medications, antihistamines, and some medications to treat nausea.

Treatments.
Doctors treat an acute closed-angle glaucoma attack with a combination of drops to constrict the pupil and drugs that reduce the eye's fluid production. They may also perform laser surgery to clear the blockage and protect sight. Without treatment, blindness can occur in that eye in as little as one to two days.

Less intense occurrences.
While this sounds dramatic and major, acute closed-angle glaucoma attacks can also strike in a less intense fashion. A person may just experience a slight blurring of vision and haloes (rainbow-colored rings around lights), without pain or redness. The attacks may end when the individual enters a well-lit room or goes to sleep and the pupil constricts, allowing the iris to pull away from the trabecular meshwork drainage system.

Predicting the chance of having an attack.
Routine examinations using a technique called gonioscopy can predict the chance of having an acute closed-angle glaucoma attack. A special lens containing a mirror is placed on the front of the eye and the width of the angle examined. If you have a narrow-angle, your doctor will warn you about early symptoms so you can seek immediate treatment if they occur. In some cases, your doctor may recommend laser surgery, to relieve pressure in the front of the eye.

Chronic Closed-Angle Glaucoma
Having closed-angle glaucoma doesn't mean a person will experience acute attacks. Instead, chronic closed-angle glaucoma may develop. In this case, the iris gradually closes over the trabecular meshwork drainage system, causing no overt symptoms. When this occurs, adhesions slowly form between the iris and the cornea. But the intraocular pressure (IOP) doesn't start to rise until enough adhesions form to cover the drainage area. If you have closed-angle glaucoma, always talk with your doctor or pharmacist before taking any prescription or over-the-counter drug or dietary supplement, since some may affect your eyes.

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