Last updated: 11/24/2009

Closed-angle glaucoma

Closed-angle glaucoma may be diagnosed in the course of a routine eye examination or during emergency treatment for symptoms of an acute attack. A doctor who is performing a standard eye examination may notice that...

the patient's eye has a shallow anterior chamber or a narrow angle between the iris and the cornea. He or she may perform one or both of the following tests to evaluate the patient's risk of developing closed-angle glaucoma. One test, called tonometry, measures the amount of fluid pressure in the eye. It is a painless procedure that involves blowing a puff of pressurized air toward the patient's eye as the patient sits near a lamp and measuring the changes in the light reflections on the patient's corneas. Other methods of tonometry involve the application of a local anesthetic to the outside of the eye and touching the cornea briefly with an instrument that measures the fluid pressure directly. The second test, gonioscopy, involves the use of a special mirrored contact lens to evaluate the anatomy of the angle between the iris and the cornea. The doctor numbs the outside of the eye with a local anesthetic and touches the outside of the cornea with the gonioscopic lens. He or she can use a slit lamp to magnify what appears on the lens. Patients with subacute, intermittent, or chronic closed-angle glaucoma can then be treated before they develop acute symptoms.

If the patient is having a sudden attack of closed-angle glaucoma, he or she will feel intense pain, and is likely to be seen on an emergency basis with the following symptoms:

• nausea and vomiting
• severe pain in or above the eye
• visual disturbances that include seeing halos around lights and hazy or foggy vision
• headache
• redness and watering in the affected eye
• a dilated pupil that does not close normally in bright light

These symptoms are produced by the sharp rise in intraocular pressure (IOP) that occurs when the angle is completely blocked. This increase can occur in a matter of hours and cause permanent loss of vision in as little as two to five days. An acute attack of closed-angle glaucoma is a medical emergency requiring immediate treatment. Emergency treatment includes application of eye drops to reduce the pressure in the eye quickly, other eye drops to shrink the size of the pupil, and acetazolamide or a similar medication to stop the production of aqueous humor. In severe cases, the patient may be given drugs intravenously to lower the intraocular pressure. After the pressure has been relieved with medications, the eye will require surgical treatment.

Melanoma of the iris

Melanoma of the iris is usually discovered in the course of a routine eye examination because it will be visible to the ophthalmologist as he or she looks through the pupil in the center of the iris. A melanoma on the iris may look like a dark spot or ring, or it may resemble tapioca. The doctor can perform a gonioscopy, and use specialized imaging studies to rule out other possible eye disorders. An ultrasound study can be made by using a small probe placed on the eye that directs sound waves in the direction of the tumor. Another test is called fluorescein angiography, which involves injecting a fluorescent dye into a vein in the patient's arm. As the dye circulates throughout the body, it is carried to the blood vessels in the back of the eye. These blood vessels can be photographed through the pupil.

In a minority of patients, melanoma of the iris is discovered because the patient is experiencing eye pain resulting from a rise in IOP caused by tumor growth.

Preparation for treatment

Patients scheduled for a laser iridotomy or iridectomy are not required to fast or make other special preparations before the procedure. They may, however, be given a sedative to help them relax. Patients scheduled for a conventional iridectomy are asked to avoid eating or drinking for about eight hours before the procedure.