Ratings of importance to the care process (A-C) and ratings of strength of evidence (I-III) are defined at the end of the "Major Recommendations" field.
Diagnosis
The initial history and physical examination includes evaluation for both primary and secondary types of angle closure. This includes the appropriate components of the comprehensive adult medical eye evaluation, (Preferred Practice Patterns Committee, "Comprehensive adult medical eye evaluation," 2005) [A:III] with particular attention to those aspects relevant to the various types of angle closure.
History
Specific questioning includes asking about the use of topical or systemic medication (e.g., sulfonamides, topiramate, phenothiazines) that may induce angle narrowing and symptoms that suggest intermittent angle-closure attacks (e.g., blurred vision, halos around lights, aching eye or brow pain, eye redness). [A:III] The patient should be asked about a family history of acute angle-closure glaucoma (Leighton, 1976; Perkins, 1974; Salmon, 1999). [B:II]
Physical Examination
If acute angle closure is present, some components of the examination may be postponed. Components of the physical evaluation that are particularly relevant for the diagnosis and management of angle closure include the following.
Assessment of Refractive Status
It is important to assess refractive status, [A:III] since hyperopic eyes, especially in older patients, have narrower anterior-chamber angles (Van Herick, Shaffer, & Schwartz, 1969) and are at increased risk of primary angle closure (PAC) (Lowe, 1970).
Pupil [A:III]
External Examination [A:III]
- Conjunctival hyperemia
- Corneal clarity
Slit-lamp Biomicroscopy [A:III]
- Central and peripheral anterior-chamber depth
- Anterior-chamber inflammation suggestive of a recent or current attack
- Corneal edema
- Iris atrophy, especially sector types; posterior synechiae; or mid-dilated pupil suggestive of a recent or current attack
- Signs of previous angle-closure attacks (Becker-Shaffer's Diagnosis, 1999) (e.g., peripheral anterior synechiae, segmental iris atrophy, glaukomflecken, posterior synechiae, pupillary dysfunction, irregular pupil)
Determination of Intraocular Pressure (IOP)
Intraocular pressure is measured in each eye, [A:III] preferably using a contact applanation method (typically a Goldmann tonometer) before gonioscopy. [A:III] Measuring central corneal thickness should be postponed until resolution of an acute attack (Aghaian et al., 2004). [A:III]
Gonioscopy
Gonioscopy of both eyes should be performed on all patients in whom angle closure is suspected. [A:III] This is required to evaluate the angle anatomy, appositional closure, and presence of peripheral anterior synechiae (Bhargava, Leighton, & Phillips, 1973). [A:III]
Other Components of the Initial Evaluation
Although a dilated examination may not be advisable in patients with anatomic narrow angles or angle closure, an attempt should be made to evaluate the fundus and optic nerve using the direct ophthalmoscope or biomicroscope. [A:III] For patients with PAC or narrow angle who are not in an acute attack, pupil dilation is contraindicated until iridotomies have been performed. [A:III] Evaluation and documentation of the optic nerve head, retinal nerve fiber layer, and visual fields may be postponed until an acute attack is adequately treated.
Management
Anatomic Narrow Angle (Primary Angle-Closure Suspect)
In patients with narrow angles, iridotomy should be considered in eyes regarded as at risk for developing angle closure. [A:III] Patients with narrow but open angles should be followed for development of IOP elevation, evidence of progressive narrowing, or development of synechial angle closure. [A:III]
Iridotomy may be indicated for eyes with narrow angles under one or more of the following additional circumstances: [A:III]
- Previously normal IOP is elevated.
- A potentially occludable angle is present.
- Peripheral anterior synechiae (PAS) that are attributable to episodes of angle closure are present.
- There is progressive narrowing of the angle.
- Medication is required that may provoke pupillary block.
- Symptoms are present that suggest prior angle closure.
- The patient's occupation/avocation makes it difficult to access immediate ophthalmic care (e.g., the patient travels frequently to developing parts of the world or works on a merchant vessel).
- For the fellow eye in patients who have had an attack of acute PAC (as described in the section about "acute primary angle closure" under Orientation)
Patients at risk for angle closure should be warned of the danger of taking medicines (e.g., over-the-counter decongestants, motion sickness medication, anticholinergic agents) that could cause pupil dilation and induce an angle-closure attack (Wolfs et al., 1997). [A:III] They should also be informed about the symptoms of acute angle-closure attacks and instructed to notify their ophthalmologist immediately if symptoms occur (Wilensky et al., 1993). [A:III]
Acute Primary Angle Closure
The definitive treatment for acute PAC is surgical, either by means of laser iridotomy or incisional iridectomy if a laser iridotomy cannot be successfully performed (Saw, Gazzard, & Friedman, 2003; "Laser peripheral iridotomy," 1994). [A:III] In acute angle-closure attacks, medical therapy is usually initiated first to lower the IOP to reduce pain and clear corneal edema in preparation for iridotomy. [A:III]
Medical therapy includes some or all of the following, based on the patient's overall physical and medical status:
- Topical beta-adrenergic antagonists
- Topical alpha2-adrenergic agonists
- Topical or systemic carbonic anhydrase inhibitors
- Topical miotics
- Systemic hyperosmotic agents
Laser iridotomy is the preferred surgical treatment because it has a favorable risk-benefit ratio ("Laser peripheral iridotomy," 1994; Robin & Pollack, 1982; Quigley, 1982). [A:II] When laser iridotomy is not possible or if the acute angle-closure attack cannot be medically broken, incisional iridectomy remains an effective alternative. [A:III] When incisional iridectomy is required and extensive synechial closure is recognized or suspected, primary filtering surgery may be considered. Patients who require bilateral incisional iridectomy should have surgery on one eye at a time (several days apart) whenever feasible to avoid simultaneous bilateral complications. [A:III]
The fellow eye of a patient with an attack of acute PAC should be evaluated since it is at high risk for a similar event. The fellow eye should receive a prophylactic iridotomy if the chamber angle is anatomically narrow, [A:II] since approximately half of fellow eyes of acute angle-closure patients will suffer acute attacks within 5 years (Saw, Gazzard, & Friedman, 2003; Bain, 1957; Wilensky et al., 1993; Edwards, 1982; Ang, Aung, & Chew, 2000).
Chronic Primary Angle Closure
Patients with chronic PAC may have elevated IOP as a result of a chronic compromise of aqueous outflow through appositional or synechial angle closure, or damage to the trabecular meshwork from the acute angle closure. In such patients, synechial angle closure usually starts superiorly in the narrowest part of the angle and may progress circumferentially. Miotics may aggravate pupillary block due to anterior rotation of the ciliary body and, when used chronically, may increase the risk of synechial angle closure, especially if cataract formation increases lens-iris contact. Peripheral iridotomy is performed to relieve the pupillary block component and this usually halts the progression of synechial closure and progressive IOP elevation.
Surgery and Postoperative Care
The plan for care prior to and after laser iridotomy or iridectomy includes the following elements:
- At least one preoperative evaluation by the surgeon (AAO, 2003) [A:III]
- Informed consent prior to surgery ("Laser peripheral iridotomy," 1994) [A:III]
- At least one IOP check within 30 to 120 minutes following surgery (Robin, Pollack, & deFaller, 1987; Rosenblatt & Luntz, 1987; Barnes et al., 1999) [A;III]
- Use of topical anti-inflammatory agents in the postoperative period, unless contraindicated [A:III]
Preoperative miotics facilitate laser iridotomy or iridectomy. Medications should be used perioperatively to avert sudden IOP elevation, particularly for patients who have severe disease (Robin, Pollack, & deFaller, 1987). [A:III]
The ophthalmologist who performs laser iridotomy or incisional iridectomy must ensure that the patient receives adequate postoperative care (AAO, 2003). [A:III]
Follow-up evaluation should include the following elements: [A:III]
- Evaluation of the patency of iridotomy
- IOP measurement
- Gonioscopy, if it was not performed immediately after iridotomy
- Pupil dilation to decrease the risk of posterior synechiae formation
- Fundus examination as clinically indicated
Lensectomy
Numerous studies document the widely held clinical impression that lensectomry significantly widens the anterior-chamber angle in eyes with narrow/occludable angels and in angle-closure glaucoma, except in plateau iris syndrome. While there is currently insufficient evidence to recommend the use of cataract surgery in the management of PAC, it can be considered with or without goniosynechialysis.
Follow-up Evaluation
Patients with a residual open angle or a mix of open angle and some PAS after laser iridotomy who also have glaucomatous optic neuropathy should be followed as specified in the Primary Open-Angle Glaucoma, Preferred Practice Pattern (PPP) (Glaucoma Panel, Preferred Practice Patterns Committee, "Primary open-angle glaucoma," 2005) [A:III]. Patients who do not have glaucomatous optic neuropathy should be followed as specified in the Primary Open-Angle Glaucoma Suspect, Preferred Practice Pattern (Glaucoma Panel, Preferred Practice Patterns Committee, "Primary open-angle glaucoma suspect," 2005) [A:III].
Provider and Setting
The performance of certain diagnostic procedures (e.g., tonometry, perimetry, pachymetry, optic disc imaging, and photography) may be delegated to appropriately trained and supervised personnel. Most diagnostic and therapeutic procedures can be undertaken safely on an outpatient basis. Hospitalization may be indicated for intensive treatment of an acute angle-closure attack so that patients can be monitored closely after surgical procedures associated with a high risk of serious short-term postoperative complications. It may also be indicated for patients in whom surgical complications have occurred or for patients who have special medical or social needs.
Counseling/Referral
If the diagnosis or management is in question or if the condition is refractory to treatment, consultation with or referral to an ophthalmologist with specialist training or experience in managing this condition may be desirable. Patients with significant visual impairment or blindness should be referred to, and encouraged to use, appropriate vision rehabilitation and social services (AAO, 2001). [A:III]
Definitions:
Ratings of Importance to Care Process:
Level A, most important
Level B, moderately important
Level C, relevant, but not critical
Ratings of Strength of Evidence:
- Level I provides strong evidence in support of the statement. The design of the study allowed the issue to be addressed, and the study was performed in the population of interest, executed in such a manner as to produce accurate and reliable data, and analyzed using appropriate statistical methods. The study produced either statistically significant results or showed no difference in results despite a design specified to have high statistical power and/or narrow confidence limits on the parameters of interest.
- Level II provides substantial evidence in support of the statement. Although the study has many of the attributes of one that provides Level I support, it lacks one or more of the components of Level I.
- Level III provides a consensus of expert opinion in the absence of evidence that meets Levels I and II.
