Closed-angle glaucoma, more commonly referred to as angle-closure glaucoma, involves a blockage in the eye, preventing drainage. The Merck Manuals explains that angle-closure glaucoma may be primary, meaning the cause is unknown, or secondary to another condition, such as diabetes. Symptoms of acute angle-closure are severe ocular pain and redness, decreased vision, colored halos around lights, headache, nausea, and vomiting due to a sudden high elevation of intraocular pressure. Immediate treatment of angle-closure glaucoma is essential to prevent optic nerve damage and vision loss. For treatment, an ophthalmologist will use medications, followed by either laser or surgical therapy.
Medications
Angle refers to the junction of the iris, the colored part of the eye, and the cornea, which form the side of the anterior chamber inside the eye. Closure refers to physical blockage of the drainage of aqueous humor due to the iris covering the drainage canals, which increases intraocular pressure. As people age, the lens of the eye grows, and a cataract may form. In some, this pushes the iris forward, narrowing the angle. The Merck Manuals notes that risk factors for developing narrow angles include: Asian ethnicity, family history and old age.
Medications used to treat acute angle-closure glaucoma include acetazolamide 500 mg, topical beta-blockers, timolol 0.5 percent and pilocarpine 2 to 4 percent to induce miosis, or constriction of the pupil. Several drugs should be given at once.
Laser Iridotomy
According to the Glaucoma Research Foundation, laser iridotomy is the most commonly performed procedure to treat angle-closure glaucoma, unless the intraocular eye pressure is very high or the optic nerve is damaged. During laser iridotomy, a laser beam makes several scars in the eye's trabecular meshwork, the eye's drainage system. This allows aqueous humor to drain from the posterior chamber to the anterior chamber of the eye, which reduces intraocular pressure.
If laser surgery does not lower eye pressure or the pressure begins to rise again, the doctor may perform filtering microsurgery.
Filtering Microsurgery
If the doctor cannot access the iris with a laser beam, she will perform filtering microsurgery, in which a small drainage hole is made in the sclera, the white part of the eye, by a procedure called a trabeculectomy. The drainage hole allows fluid to flow out of the eye and helps lower eye pressure.
The Glaucoma Research Foundation states that glaucoma filtering microsurgery has a 70 to 90 percent success rate for at least one year. Occasionally, the surgically created drainage hole begins to close, and the pressure rises again. Consequently, this procedure may be repeated a number of times.
