Chronic angle-closure glaucoma

I.        Describe the approach to establishing the diagnosis

A.     Describe the etiology of this disease

1.      Peripheral iris bowing

a.      Prolonged apposition or repeated subacute attacks lead to gradual peripheral anterior synechia (PAS) formation¹

b.      PAS begin as pinpoint synechiae reaching to the midtrabecular meshwork and then gradually expand in width¹

2.      Circumferential closure beginning at the deepest portions of the angle¹

a.      Occurs more commonly in eyes with darker irides¹

b.      Closure occurs more evenly in all quadrants¹

B.     Define the relevant aspects of epidemiology of this disease

1.      Race

a.      Frequency is highest among Alaskan and Greenland Inuits and among other Asian groups (Chinese Asian, Southeast Asian, and Asian Indians)

2.      Sex - higher prevalence in women

3.      Refraction-typically associated with hyperopia

4.      Creeping angle-closure is relatively uncommon in whites but much more prevalent in Asians¹

5.      Black patients with angle-closure tend to have creeping angle-closure¹

C.    List the pertinent elements of the history

1.      Prior history of acute angle-closure glaucoma

2.      Prior history of subacute angle-closure glaucoma

D.    Describe pertinent clinical features

1.      Elevated intraocular pressure (IOP)

2.      Permanent PAS on indentation (compression) gonioscopy

3.      Clinical course resembles that of open-angle glaucoma

a.      Modest variable elevation of IOP

b.      Progressive cupping of the optic nerve head

c.      Glaucomatous visual field (VF) loss

d.      Lack of symptoms

4.      Some eyes may eventually develop an acute attack of angle-closure glaucoma with pupillary block

5.      Glaukomflecken and/or sector iris atrophy as indicators of previous attacks of angle-closure glaucoma

II.      Define the risk factors

A.     Hyperopia

B.     Family history of angle-closure

C.    Inuit or Asian ethnic groups (mentioned above)

D.    Older age

E.     Female gender

III.    List the differential diagnosis

A.     Neovascular glaucoma

B.     Iridocorneal endothelial syndrome (particularly Chandler syndrome)

C.    Inflammatory glaucoma

D.    Phacomorphic glaucoma

E.     Ciliary body swelling, cysts

F.     Aqueous misdirection

G.    Posterior segment tumors

H.     Scleral buckling procedures

I.         Plateau iris

IV.   Describe patient management in terms of treatment and follow-up

A.     Describe medical therapy options

1.      Miotics – higher strength miotics and prolonged use of miotics may exacerbate the condition by aggravating pupillary block

2.      Beta-adrenergic antagonists

3.      Alpha-adrenergic agonists (sympathomimetics)

4.      Carbonic anhydrase inhibitors

5.      Prostaglandin analogues

B.     Describe the surgical therapy options

1.      Laser peripheral iridotomy-this may eliminate any element of pupillary block but may not lower IOP

2.      Surgical iridectomy if laser surgery not possible

3.      Surgical filtering procedures

4.      Laser iridoplasty

5.      Cataract extraction may be indicated in selected cases and possibly could be more effective than laser or surgical peripheral iridotomy in preventing further extension of peripheral anterior synechiae

V.   List the complications of treatment, their prevention and management

A.     Inflammation may follow all laser surgeries and surgical procedures, treat with topical corticosteroids following iridoplasty and iridotomy

VI.   Describe disease-related complications

A.     Endstage glaucoma with severe visual field loss and eventual loss of central vision

B.     IOP generally rises slowly or is intermittently elevated  so that pain or visual symptoms are unusual complications

VII.   Describe appropriate patient instructions

A.     Instruct in need for regular follow up exams as patient may not have any obvious symptoms of disease

B.     Patients need to realize that laser iridotomy will probably not cure disease and additional treatment will almost certainly be warranted

C.    Patients should be informed of the chronic nature of the disease and the need for lifelong follow-up

Additional Resources

1. Ritch R, Lowe RF.  Angle-closure glaucoma: Clinical types.  In:  Ritch R, Shields MB, Krupin T, eds.  The Glaucomas, 2^nd ed.  St. Louis, MO:  1996:  825-827.

2. AAO, Basic and Clinical Science Course.  Section 10: Glaucoma, 2004-2005.

3. AAO, Focal Points: Diagnosis and Management of Angle-Closure Glaucoma, Module #10, 1988.

4. AAO, Glaucoma Medical Therapy: Principles and Management, 1999, p.198-199.