From the Guidelines
A flat anterior chamber in the context of acute angle closure requires immediate treatment with laser iridotomy as the preferred surgical option to relieve pupillary block and prevent further complications, as recommended by the most recent guidelines 1. The management of a flat anterior chamber, particularly in the setting of acute angle closure, involves a multi-step approach to reduce intraocular pressure (IOP), alleviate pupillary block, and prevent long-term damage to the eye.
- Initial medical therapy may include topical beta-adrenergic antagonists, alpha2-adrenergic agonists, carbonic anhydrase inhibitors, and hyperosmotic agents to lower IOP and reduce pain 1.
- However, laser iridotomy is the preferred surgical treatment due to its favorable risk-benefit ratio, as it can relieve pupillary block, prevent the formation of peripheral anterior synechiae (PAS), and result in significant angle widening and iris-profile flattening 1.
- In cases where laser iridotomy cannot be performed immediately due to corneal edema or iris congestion, alternative procedures such as laser peripheral iridoplasty (LPI), paracentesis, or incisional iridectomy may be considered, with the goal of eventually performing a definitive laser iridotomy once the acute attack is broken 1.
- The selection of additional treatments, such as primary phacoemulsification or cyclophotocoagulation, should be based on the individual patient's condition and the discretion of the treating ophthalmologist, as the current evidence is limited 1.
- It is crucial to address the flat anterior chamber promptly to prevent complications such as corneal decompensation, cataract formation, or permanent vision loss, emphasizing the need for urgent ophthalmological consultation and timely intervention.
From the Research
Causes of Flat Anterior Chamber
- A flat anterior chamber can occur after filtering surgery for glaucoma, and is often associated with cornea-lens touch, hypotony, and absence of wound leakage 2
- It can also be caused by overfiltration after trabeculectomy, leading to a shallow or flat anterior chamber 3, 4
- Other causes include pupillary block and ciliary block, which can result in a flat anterior chamber 5
Management of Flat Anterior Chamber
- Medical therapy, including frequent topical application of atropine sulfate, may be effective in some cases, but prompt surgical reformation of the anterior chamber and drainage of any suprachoroidal fluid may be necessary in others 2
- The use of viscoelastic substances, such as Healon5, can help to stabilize the anterior chamber and facilitate filtration 3
- Surgical procedures, such as the application of additional sutures and excision of the overfiltering bleb, may be necessary in some cases 5
- Pharmacologic therapy with atropine, phenylephrine, and oral acetazolamide may also be effective in managing a flat anterior chamber 4
Risk Factors for Flat Anterior Chamber
- Older age, oral carbonic anhydrase inhibitor use at tube opening, and higher intraocular pressure before tube opening are independent predictors of flat anterior chamber requiring intervention after glaucoma drainage implant surgery 6
- Female sex, history of diabetes, hypertension, and pseudoexfoliation may also be risk factors for flat anterior chamber 6