What is the recommended treatment for bilateral anatomical narrow angle anterior chamber?

Treatment for Bilateral Anatomical Narrow Angle Anterior Chamber

Laser peripheral iridotomy (LPI) is the recommended first-line treatment for bilateral anatomical narrow angle anterior chamber to prevent progression to angle closure and associated complications. 1

Primary Treatment Approach

• LPI should be performed promptly in both eyes with anatomically narrow angles to eliminate pupillary block, which is the primary mechanism of angle closure 1
• Prophylactic LPI is effective in preventing acute angle-closure crisis (AACC), with approximately half of untreated narrow angle eyes developing AACC within 5 years 1
• LPI results in significant widening of the anterior chamber angle in most patients with narrow angles 2, 3
• Bilateral same-day LPI can be safely performed when access to care is limited 4

Medical Management

• Chronic parasympathomimetic therapy (e.g., pilocarpine) is NOT an appropriate alternative to LPI for treatment of narrow angles 1
• About 40% of eyes treated with miotics alone can develop AACC within 5 years, and many develop progressive synechial angle closure with miotic use 1
• While pilocarpine can temporarily widen the angle, LPI provides greater and more sustainable angle widening without anterior chamber shallowing 5
• Brinzolamide and other aqueous suppressants may be used as adjunctive therapy but are not definitive treatments for anatomical narrow angles 6

Post-LPI Considerations

• Despite LPI, approximately 19-57% of eyes may still have residual angle closure, particularly when non-pupillary block mechanisms are present 2, 3
• Risk factors for persistent angle closure after LPI include thicker iris, anteriorly positioned ciliary body, and greater lens vault 3
• Follow-up gonioscopy is essential to monitor for increasing peripheral anterior synechiae (PAS) or development of secondary angle closure 1

Alternative and Adjunctive Treatments

• For patients with plateau iris configuration after LPI, additional treatment options include:

  • Laser peripheral iridoplasty, which can improve mid-to-peripheral anterior chamber depth beyond what LPI alone achieves 7
  • Chronic miotic therapy or other surgical procedures may be considered 1

• Lens extraction (phacoemulsification) should be considered in cases where:

  • LPI is insufficient to control intraocular pressure (IOP) 1
  • The EAGLE study demonstrated clear lens extraction to be superior to LPI for IOP control in primary angle closure (PAC) with elevated IOP and primary angle-closure glaucoma (PACG) 1
  • Lens extraction significantly widens the anterior chamber angle and can lower postoperative medication requirements 1

Complications and Monitoring

• Potential complications of LPI include:

  • IOP spikes (6-10% of patients) 4, 3
  • Anterior chamber bleeding (30-41%) 3
  • Dysphotopsia/glare (2-11%) 4, 3
  • Cataract progression (23-39%) 3

• Regular follow-up is required to monitor for:

  • Development of peripheral anterior synechiae 1
  • Progression to primary angle closure glaucoma (PACG), though this is uncommon with proper treatment (0-0.3% per year in PAC suspects) 3
  • Need for additional interventions to control IOP 3

Special Considerations

• For patients with plateau iris syndrome (persistent angle closure after LPI), additional treatment may include iridoplasty, chronic miotic therapy, or lens extraction 1
• Cautious dilation may be performed if necessary for retinal examination, but only after LPI has been completed 1
• In cases where LPI cannot be performed, incisional iridectomy remains an effective alternative 1