Acute Angle-Closure Glaucoma (AACG) Treatment & Management

The definitive treatment of acute angle closure (AAC) is surgical. The goal of medical treatment is to break the AAC in preparation for surgical intervention to prevent its recurrence.

Topical and oral medications are used to lower the IOP. Lowering the IOP minimizes damage to the optic nerve and allows the ocular tissue to be compressed.

If the IOP cannot be lowered sufficiently, an anterior chamber paracentesis (needle insertion) can be performed. This technique can be useful because it provides immediate relief to the distressed patient and facilitates tolerance of subsequent treatment. A consent form should be obtained for the risks (eg, inadvertent lens puncture, decompression retinopathy) and benefits prior to the procedure.

Compression gonioscopy is then performed by using a gonioscope to push down on the cornea and then easing up on it. The process is done repeatedly, and the force generated is translated intraocularly to break the contact between the iris and the lens (pupillary block) and apposition of the iris to the trabecular meshwork (angle closure). This temporarily restores the outflow of aqueous humor and normalizes the IOP.

Patients may also be placed in a supine position to allow the lens to move away from the anterior chamber to help restore of the flow of aqueous humor.

When the eye is in AAC, the visualization into the anterior chamber is poor. Medications for eye pressure and inflammation are used to help clear up the cornea, to reduce intraocular inflammation, and to decrease iris edema. It is preferable to perform laser iridotomy when the condition can be optimized. If laser iridotomy cannot be performed and AAC continues, surgical iridectomy is indicated.

Laser iridotomy

The treatment of choice for pupillary-block ACG is laser iridotomy. Iridotomy with an argon and/or Nd:YAG laser creates an opening in the iris through which aqueous humor trapped in the posterior chamber can reach the anterior chamber and trabecular meshwork. As aqueous humor flows into the anterior chamber through the iris defect, pressure behind the iris falls, allowing the iris to fall back toward its normal position. This procedure opens the anterior chamber angle and relieves the blockade of trabecular meshwork. It also prevents future pupillary block and AAC.

Surgical iridectomy

If the cornea is extremely cloudy or the iris is too thick and an opening cannot be created using laser, incisional peripheral iridectomy can be performed in the operating room.

Laser iridoplasty

Argon laser may be used to create burns in the peripheral iris and to cause tissue contraction. This reduces iris thickness and creates additional space between the iris and the trabecular meshwork. Traditionally, this technique is indicated to prevent AAC in plateau iris and nanophthalmos but can also be used to augment the effect of iridotomy or iridectomy, if needed. ^{[15, 16]}

Cataract surgery

If the angle continues to be narrow and occludable after laser iridotomy and iridoplasty, especially in an older patient, cataract surgery is indicated to remove the cataract and its mass effect on the angle. If the patient has both a narrow occludable angle and a visually significant cataract (blurry vision due to cataract), cataract surgery is the treatment of choice. It opens the angle and improves vision. ^[17] Even without significant cataract, effectiveness of early lens extraction for the treatment of primary angle-closure glaucoma (EAGLE) study, conducted in Asia, showed that clear lens extraction may be more efficacious and cost effective than laser iridotomy. The authors suggested that the crystalline lens may play a larger role in the mechanism of angle closure than previously thought and that early lens extraction can be considered as an option for first-line treatment. ^[18]

Goniosynechialysis

If the patient undergoes cataract surgery and there are bands of adhesion between the iris and the trabecular meshwork, the bands may be pulled apart during surgery to restore the flow of aqueous humor through the trabecular meshwork.

Glaucoma surgery

If permanent adhesions between the iris and trabecular meshwork have formed after AAC and IOP cannot be normalized with the other methods, traditional glaucoma surgery, such as a trabeculectomy or tube shunt, may be indicated.

Some of the potential complications AAC include the following:

• Cataract formation
• Iris sphincter atrophy and permanently dilated pupil
• Peripheral anterior synechia
• Chronic angle closure glaucoma
• Absolute glaucoma
• Corneal decompensation
• Optic atrophy

In most cases, the fellow eye has an occludable angle, and laser iridotomy should be performed as soon as possible.

The patient needs to be monitored closely after the initial acute angle closure (AAC) to ensure the following:

• The IOP is normalized and AAC does not recur.
• Perform laser iridotomy once there is sufficient view into the anterior chamber.
• Ensure the laser treatment is effective or if additional treatment, such as iridoplasty, is indicated.
• Treat the patient until the inflammation has subsided and the pupil and vision return to normal. Gradually taper the medications.
• Assess the contralateral eye and perform laser treatment, if needed.

Patients in AAC needs to be treated until the IOP normalizes. IOP can increase after laser iridotomy, and the IOP should be checked 30-60 minutes after the treatment prior to releasing the patient.