Guideline:Primary open-angle glaucoma. Measure Summary

Primary open-angle glaucoma

Note: Primary open-angle glaucoma is a progressive, chronic optic neuropathy in adults in which intraocular pressure (IOP) and other currently unknown factors contribute to damage and in which, in the absence of other identifiable causes, there is a characteristic acquired atrophy of the optic nerve and loss of retinal ganglion cells and their axons.

To identify and treat primary open-angle glaucoma (POAG) and to preserve visual function while minimizing adverse effects of therapy, thereby enhancing the patient's health and quality of life by addressing the following goals:

• Document the status of optic nerve structure and function on presentation
• Estimate an intraocular pressure (IOP) below which further optic nerve damage is unlikely to occur.
• Attempt to maintain IOP at or below this target level by initiating appropriate therapeutic intervention(s)
• Monitor the structure and function of the optic nerve for further damage and adjust the target IOP to a lower level if deterioration occurs
• Minimize the side effects of treatment and their impact on the patient's vision, general health, and quality of life
• Educate and involve the patient and appropriate family members/caregivers in the management of the disease

Adults 18 or older with primary open-angle glaucoma (POAG)

Diagnosis

1. Evaluation of visual function through questionnaires and patient assessment
2. Ophthalmic evaluation
   • History, including ocular, family and systemic
   • Visual acuity measurement
   • Pupil examination
   • Anterior segment examination
   • Intraocular pressure measurement
   • Gonioscopy
   • Optic nerve head and retinal nerve fiber layer examination
   • Fundus examination
3. Supplemental ophthalmic testing

Management/Treatment

1. Medical treatment
   • Prostaglandin analogs and beta-blockers (most frequently used)
   • Alpha-adrenergic agonists, parasympathomimetic agents, and topical and oral carbonic anhydrase inhibitors
2. Laser trabeculoplasty
3. Incisional glaucoma surgery
4. Cyclodestructive surgery
5. Periodic follow-up, including history, physical examination, gonioscopy, and adjustment of therapy, as needed
6. Risk assessment
7. Patient education, counseling, and referral

In the process of revising this document, a literature search of the Cochrane Library and PubMed was conducted on December 3, 2008 and April 24, 2009 on the subject of primary open-angle glaucoma (POAG) for the years 2004 to the date of the search. In addition, the evidence synthesis prepared by the British National Collaborating Centre for Acute Care for the National Institute for Health and Clinical Excellence clinical guideline on Glaucoma: diagnosis and management of chronic open-angle glaucoma and ocular hypertension was reviewed.

Not stated

Ratings of Strength of Evidence

Level I includes evidence obtained from at least one properly conducted, well-designed, randomized controlled trial. It could include meta-analyses of randomized controlled trials.

Level II includes evidence obtained from the following:

• Well-designed controlled trials without randomization
• Well-designed cohort or case-control analytic studies, preferably from more than one center
• Multiple-time series with or without the intervention

Level III includes evidence obtained from one of the following:

• Descriptive studies
• Case reports
• Reports of expert committees/organizations (e.g., Preferred Practice Pattern [PPP] panel consensus with external peer review)

Not stated

The results of the literature search were reviewed by the Glaucoma Panel and used to prepare the recommendations, which they rated in two ways. The panel first rated each recommendation according to its importance to the care process. This "importance to the care process" rating represents care that the panel thought would improve the quality of the patient's care in a meaningful way. The panel also rated each recommendation on the strength of evidence in the available literature to support the recommendation made.

Ratings of Importance to Care Process

Level A, defined as most important

Level B, defined as moderately important

Level C, defined as relevant but not critical

The guideline developers reviewed published cost analyses.

These guidelines were reviewed by Council and approved by the Board of Trustees of the American Academy of Ophthalmology (September 2010).

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 comprehensive initial glaucoma evaluation (history and physical examination) includes all components of the comprehensive adult medical eye evaluation in the addition to and with special attention to those factors that specifically bear upon the diagnosis, course, and treatment of primary open-angle glaucoma (POAG).

Evaluation of Visual Function

Self-reported functional status or difficulty with vision can be assessed either by patient complaints or by using specific questionnaires, including the National Eye Institute-Visual Function Questionnaire-25. (Freeman et al., 2008; Gutierrez et al., 1997; Lee et al., 1998; Parrish et al., 1997; Wilson et al., 1998; Aspinall et al., 2008; Goldberg et al., 2009; Spaeth, Walt, & Keener, 2006) [A:III]

Ophthalmic Evaluation

History

• Ocular [A:III], family (Dielemans et al., 1994; Wolfs et al., 1998; Tielsch et al., 1994) [A:II], and systemic history (e.g., asthma). [A:III] The severity and outcome of glaucoma in family members, including history of visual loss from glaucoma, should be obtained during initial evaluation. (Wolfs et al., 1998; Tielsch et al., 1994) [B:III]
• Review of pertinent records, [A:III] with particular reference to the past intraocular pressure (IOP) levels, status of the optic nerve, and visual field. [A:III]
• Current ocular and systemic medications (e.g., corticosteroids) and known local or systemic intolerance to ocular or systemic medications. [A:III]
• Ocular surgery. [A:III]

Visual Acuity Measurement

Visual acuity with current correction (the power of the present correction recorded) at distance and, when appropriate, at near should be measured. [A:III] Refraction may be indicated to obtain the best-corrected visual acuity.

Pupil Examination

The pupils are examined for reactivity and an afferent pupillary defect (Kohn, Moss, & Podos, 1979; Brown et al., 1987; Kerrison et al., 2001). [B:II]

Anterior Segment Examination

A slit-lamp biomicroscopic examination of the anterior segment can provide evidence of physical findings associated with narrow angles, such as shallow peripheral anterior chamber depth and crowded anterior chamber angle anatomy, corneal pathology, or a secondary mechanism for elevated IOP such as pseudoexfoliation (exfoliation syndrome), pigment dispersion with Krukenberg spindle and/or iris transillumination defects, iris and angle neovascularization, or inflammation. [A:III]

Intraocular Pressure Measurement

Intraocular pressure is measured in each eye, preferably by Goldmann applanation tonometry, before gonioscopy or dilation of the pupil (Kass et al., 2002; Collaborative Normal-Tension Glaucoma Study Group, 1998; Leske et al., 2003; Heijl et al., 2002; The Advanced Glaucoma Intervention Study (AGIS), 2000; Jay & Allan, 1989; The Glaucoma Laser Trial (GLT), 1990; GLT, 1995; Ederer et al., 2004; Gordon & Kass, 1999; Lichter et al., 2001; Migdal, Gregory, & Hitchings, 1994; Jay & Murray, 1988; Whitacre & Stein, 1993). [A:I] Recording time of day of IOP measurements may be helpful to assess diurnal variation. Unrecognized fluctuations in IOP may lead to progression of POAG (Barkana et al., 2006; Hasegawa et al., 2006; Dinn et al., 2007; Bagga, Liu, & Weinreb, 2009). Therefore, additional measurements may be indicated, either at different hours of the day on the same day or on different days.

Gonioscopy

The diagnosis of POAG requires careful evaluation of the anterior chamber angle to exclude angle closure or secondary causes of IOP elevation, such as angle recession, pigment dispersion, peripheral anterior synechiae, angle neovascularization, and inflammatory precipitates (Tasman & Jaeger, 2009). [A:III]

Optic Nerve Head and Retinal Nerve Fiber Layer Examination

The preferred technique for optic nerve head and retinal nerve fiber layer evaluation involves magnified stereoscopic visualization (as with the slit-lamp biomicroscope), preferably through a dilated pupil. [A:III]

Fundus Examination

Examination of the fundus, through a dilated pupil whenever feasible, includes a search for other abnormalities that may account for optic nerve changes and/or visual field defects (e.g., optic nerve pallor, disc drusen, optic nerve pits, disc edema from central nervous system disease, macular degeneration, retinovascular occlusion, and other retinal disease). [A:III]

Supplemental Ophthalmic Testing

Central Corneal Thickness (CCT) Measurement

Measurement of CCT aids the interpretation of IOP readings and helps to stratify patient risk for ocular damage (Gordon et al., 2002; Medeiros et al., 2003; Dueker et al., 2007; Agudelo, Molina, & Alvarez, 2002). [A:II]

Visual Field Evaluation

Automated static threshold perimetry is the preferred technique for evaluating the visual field (Delgado et al., 2002). [A:III] Careful manual combined kinetic and static threshold testing (e.g., Goldmann visual fields) is an acceptable alternative when patients cannot perform automated perimetry reliably or if it is not available. [A:III] Repeat, confirmatory visual field examinations may be required for test results that are unreliable or show a new glaucomatous defect before changing management (Collaborative Normal-Tension Glaucoma Study Group, 1998; Gordon & Kass, 1999). [A:III]

Optic Nerve Head and Retinal Nerve Fiber Layer Analysis

The appearance of the optic nerve should be documented (Lin et al., 2007; Singh et al., 2008). [A:II] Color stereophotography is an accepted method for documenting optic nerve head appearance. Computer-based image analysis of the optic nerve head and retinal nerve fiber layer is an alternative for documentation of the optic nerve. In the absence of these technologies, a nonstereoscopic photograph or a drawing of the optic nerve head should be recorded, but these are less desirable alternatives to stereophotography or computer-based imaging (Shaffer et al., 1975). [A:III]

Management

Goals

The goals of managing patients with POAG are to achieve the following:

• Controlled IOP in the target range
• Stable optic nerve/retinal nerve fiber layer status
• Stable visual fields

Because elevated IOP is a treatable cause of POAG damage, one can expect to reduce the risk of disease progression in many patients by lowering the IOP by means of medication, laser therapy, or incisional glaucoma surgery. Results from randomized controlled trials (summarized in Table 2 of the original guideline document) and other studies reinforce this expectation and provide evidence that the more the IOP is lowered, the more likely is it to slow the rate of progression of POAG.

The effects of treatment, the patient's quality of life, and the patient's life expectancy are important to consider when choosing therapy. The diagnosis, severity of the disease, prognosis and management plan, and likelihood of long-term therapy should be discussed with the patient. [A:III]

Target Intraocular Pressure for Patients with POAG

The goal of glaucoma treatment is to maintain the IOP in a range at which a patient is likely to remain stable or at which worsening of glaucoma will be slow enough that the risk of additional intervention is not justified. The estimated upper limit of that range is considered the "target pressure." The initial target pressure is an estimate and a means toward the ultimate goal of protecting the patient's vision. The target pressure should be individualized and may need adjustment during the course of the disease. [A:III]

When initiating therapy, the ophthalmologist assumes that the measured pretreatment pressure range contributed to optic nerve damage and is likely to cause additional damage in the future. Lowering the pretreatment IOP by 25% or more has been shown to inhibit progression of POAG (Collaborative Normal-Tension Glaucoma Study Group, 1998; Leske et al., 2003; Heijl et al., 2002; AGIS, 2000; Ederer et al., 2004; Lichter et al., 2001). [A:II] It is reasonable to select an initial target pressure at least 25% lower than pretreatment levels. Choosing an even lower target IOP can be justified if there is more severe optic nerve damage, if the damage is progressing rapidly, or if other risk factors such as family history, age, or disc hemorrhages are present (see "Risk Factors for Progression" in the original guideline document). Choosing a less aggressive target IOP may be reasonable if the risks of aggressive treatment outweigh the benefits (e.g., if a patient does not tolerate medical therapy well and surgical intervention would be difficult or if the patient's life expectancy is short).

The adequacy and validity of the target pressure are periodically reassessed by comparing optic nerve status (by optic disc appearance, quantitative assessments of the disc and nerve fiber layer, and visual field tests) with previous examinations. If progression occurs at the target pressure, undetected IOP fluctuations and adherence to therapy can be re-evaluated before adjusting the target IOP. However, target pressure is an estimate, and all treatment decisions must be individualized according to the needs of the patient.

Therapeutic Choices

The IOP can be lowered by medical treatment, laser therapy, or incisional glaucoma surgery (alone or in combination). The choice of initial therapy depends on numerous considerations, and discussion of treatment with the patient should include the relative risks and benefits of the three options. [A:III]

Medical Treatment

Unless contraindicated, medical therapy is presently the most common initial intervention to lower IOP. If target IOP is not achieved by one medication, then additional separate medications, combination therapies or switching of treatments may be considered to reach the target IOP.

Prostaglandin analogs and beta blockers are the most frequently used initial eye drops for lowering IOP in patients with glaucoma. Prostaglandin analogs are the most effective drugs at lowering IOP and can be considered as initial medical therapy unless other considerations such as cost, side effects intolerance or patient refusal preclude this. [A:I] Other agents in addition to prostaglandin analogs and beta-blockers include alpha₂ adrenergic agonists, parasympathomimetics, and topical and oral carbonic anhydrase inhibitors.

The ophthalmologist should consider the balance between side effects and effectiveness in choosing a regimen of maximal effectiveness and tolerance to achieve the desired IOP reduction for each patient. [A:III] Frequent dosing and side effects (such as depression, exercise intolerance, and impotence with topical beta-blockers) may affect adherence to therapy.

The patient and ophthalmologist together decide on a practical and feasible regimen to follow in terms of dosing, cost, and adherence in the context of the patient's age and preferences. The ophthalmologist should assess the patient who is being treated with glaucoma medication for local ocular and systemic side effects; toxicity, including interactions with other medications; and potential life-threatening adverse reactions (Fung et al., 2007). [A:III] To reduce systemic absorption, patients should be educated about eyelid closure or nasolacrimal duct occlusion when applying topical medications.

At each examination, medication dosage and frequency of use should be recorded. [A:III] Reviewing the time medication was taken may be useful. Adherence to the therapeutic regimen and recommendations for therapeutic alternatives or diagnostic procedures should be discussed. [A:III]

Laser Trabeculoplasty

Laser trabeculoplasty can be considered as initial therapy in selected patients [A:I] or an alternative for patients who cannot or will not use medications reliably due to cost, memory problems, difficulty with instillation, or intolerance to the medication. Laser trabeculoplasty lowers IOP by improving aqueous outflow and can be performed using argon, diode, and frequency-doubled YAG lasers.

Perioperative Care in Laser Trabeculoplasty

The ophthalmologist who performs the laser surgery has the following responsibilities: (American Academy of Ophthalmology, "Pretreatment assessment," 2006; American Academy of Ophthalmology, "An ophthalmologist's duties," 2006). [A:III]

• To obtain informed consent from the patient or the patient's surrogate decision maker after discussing the risks, benefits, and expected outcomes of surgery [A:III]
• To ensure that the preoperative evaluation confirms the need for surgery [A:III]
• To perform at least one IOP check within 30 minutes to 2 hours of surgery (Robin, 1991) [A:I]
• To perform a follow-up examination within 6 weeks of surgery or sooner if there is concern about IOP-related damage to the optic nerve during this time (Spaeth & Baez, 1992; Wickham & Worthen, 1979; Wise & Witter, 1979; Schwartz et al., 1981) [A:III]

Medications that are not being used chronically may be used perioperatively to avert temporary IOP elevations, particularly in those patients with severe disease.

Incisional Glaucoma Surgery

Trabeculectomy

Filtering surgery is effective in lowering IOP; it is generally indicated when medicine or laser therapy is insufficient to control disease and can be considered in selected cases as initial therapy (Musch et al., 2009; Parrish et al., 2009). [A:I]

Antifibrotic agents may be used intraoperatively and postoperatively to reduce the subconjunctival scarring after filtration surgery that can result in failure of the operation. The use of intraoperative mitomycin-C reduces the risk of surgical failure both in eyes at high risk of surgical failure and in eyes that have not undergone previous surgery. The use of postoperative injections of 5-fluorouracil also reduces the likelihood of surgical failure in both high-risk eyes and eyes that have not undergone previous surgery.

The use of an antifibrotic agent carries with it an increased likelihood of bleb-related complications such as hypotony, hypotony maculopathy, late-onset bleb leak, and late-onset infection that must be weighed against the benefits when deciding whether or not to use these agents. These complications may be even more common in primary filtering surgery of phakic patients.

Aqueous Shunts

Aqueous shunts have traditionally been used to manage medically uncontrolled glaucoma when trabeculectomy has failed to control IOP or is deemed unlikely to succeed. This includes eyes with neovascular glaucoma, uveitic glaucoma, extensive conjunctival scarring from previous ocular surgery or cicatrizing diseases of the conjunctiva, and congenital glaucoma in which angle surgery has failed. However, the indications for using aqueous shunts have been broadening, and these devices are being increasingly utilized in the surgical management of glaucoma.

Aqueous shunts are associated with intraoperative and postoperative complications that are similar to those that occur with trabeculectomy. In addition, they have unique complications related to implantation of a foreign body. Erosion of the tube may occur through the conjunctiva, and this typically develops a few millimeters behind the limbus following anterior chamber insertion. Diplopia may result from extraocular muscle fibrosis or a mass effect of the bleb overlying the end plate. Tube-cornea touch can lead to progressive endothelial cell loss and persistent corneal edema. The risk of postoperative infection appears to be less with aqueous shunts than after trabeculectomy with an antifibrotic agent.

Combined Surgeries

Patients with POAG who have a visually significant cataract have a range of options to consider. If IOP control is at target on one or few medications, cataract surgery alone may be adequate, with the additional benefit that it may lower IOP slightly. If IOP is markedly uncontrolled on several medications after laser trabeculoplasty and the patient has a moderate cataract, then glaucoma surgery may be indicated initially, with the plan to perform cataract surgery once IOP is adequately controlled. In between these two extremes, the decision of which procedure(s) to perform first or whether to combine cataract and glaucoma surgery is determined by the ophthalmologist and patient after discussion of the risks and benefits of each course of action.

Cataract surgery with intraocular lens (IOL) implantation alone results in a modest reduction in IOP of less than 2 mm Hg on average. Generally, combined cataract and glaucoma surgery is not as effective as glaucoma surgery alone in lowering IOP, so patients who require filtration surgery who also have mild cataract may be better served by filtration surgery alone and cataract surgery later. [B:III] The use of mitomycin-C, but not 5-flurouracil, results in lower IOP in combined procedures.

Potential benefits of a combined procedure (cataract extraction with IOL implantation and trabeculectomy) are protection against the IOP rise that may complicate cataract surgery alone and the possibility of achieving long-term glaucoma control with a single operation. Therefore, an ophthalmologist may reasonably choose to perform a combined surgery due to these perceived advantages to an individual patient. Despite these presumed advantages, the evidence to date does not support routinely combining cataract and glaucoma surgery for all patients, because IOP outcomes with two-stage surgery are likely similar. Additionally, combined procedures are technically more complex. Ultimately, however, the decision of which surgical route to pursue is best left to the treating ophthalmologist and the individual patient.

Other types of glaucoma surgery can also be combined with cataract surgery, such as implantation of glaucoma drainage devices and endocyclophotocoagulation (see discussion in next section). Combined cataract and glaucoma drainage device surgery can also improve vision while providing IOP control.

Other Glaucoma Surgeries

Nonpenetrating glaucoma surgery is an alternative to trabeculectomy. The precise role of nonpenetrating surgery in the surgical management of glaucoma remains to be determined. The two main types of nonpenetrating glaucoma surgery are viscocanalostomy and nonpenetrating deep sclerectomy. The rationale for nonpenetrating glaucoma surgery is that by avoiding a continuous passageway from the anterior chamber to the subconjunctival space, the incidence of complications such as bleb-related problems and hypotony can be reduced. The nonpenetrating procedures have a higher degree of surgical difficulty compared with trabeculectomy and require special instrumentation. Randomized clinical trials comparing viscocanalostomy with trabeculectomy generally suggest greater IOP reduction with trabeculectomy, but more complications with viscocanalostomy.

Perioperative Care in Incisional Glaucoma Surgery

The ophthalmologist who performs incisional glaucoma surgery has the following responsibilities: (American Academy of Ophthalmology, "Pretreatment Assessment," 2006; American Academy of Ophthalmology, "An Ophthalmologist's Duties," 2006) [A:III]

• Obtain informed consent from the patient or the patient's surrogate decision maker after discussing the risks, benefits, and expected outcomes of surgery (Jonsen, Siegler, & Winslade, 1992 [A:III]
• Ensure that the preoperative evaluation accurately documents the findings and indications for surgery [A:III]
• Prescribe topical corticosteroids in the postoperative period (Roth et al., 1991; Starita et al., 1985) [A:II]
• Perform a follow-up evaluation on the first postoperative day (12 to 36 hours after surgery) and at least once during the first 1 to 2 weeks to evaluate visual acuity, IOP, and status of the anterior segment (Stewart & Shields, 1988; Fiore et al., 1989; Phillips, Clark, & Levy, 1987; Brubaker & Pederson, 1983; Gressel, Parrish, & Heuer, 1984; Ruderman, Harbin, & Campbell, 1986) [A:II]
• In the absence of complications, perform additional postoperative visits during a 6-week period to evaluate visual acuity, IOP, and status of the anterior segment (Stewart & Shields, 1988; Fiore et al., 1989; Phillips, Clark, & Levy, 1987; Brubaker & Pederson, 1983; Gressel, Parrish, & Heuer, 1984; Ruderman, Harbin, & Campbell, 1986) [A:III]
• Schedule more frequent follow-up visits, as necessary, for patients with postoperative complications such as a flat or shallow anterior chamber or evidence of early bleb failure, increased inflammation, or Tenon's encapsulated bleb formation (Stewart & Shields, 1988; Fiore et al., 1989; Phillips, Clark, & Levy, 1987; Brubaker & Pederson, 1983; Gressel, Parrish, & Heuer, 1984; Ruderman, Harbin, & Campbell, 1986) [A:III]
• Undertake additional treatments as necessary, including injection of antifibrotic agents, repair of bleb leaks, bleb massage, suture lysis, bleb needling, or other surgical revisions of the bleb or surgical procedures to correct a flat anterior chamber to maximize the chances for a successful long-term result (Radhakrishnan et al., 2009; Kapasi & Birt, 2009; Anand & Khan, 2009) [A:III]
• Explain that filtration surgery places the eye at risk for endophthalmitis for the duration of the patient's life, and that if the patient has symptoms of pain and decreased vision and the signs of redness and discharge, he or she should notify the ophthalmologist immediately (Sharan et al., 2009) [A:III]

Cyclodestructive Surgery

Cyclodestructive procedures reduce the rate of aqueous production. There are several ways to reduce ciliary body function, such as cyclocryotherapy, transscleral and noncontact Nd:YAG laser, and transscleral and noncontact endodiode laser cyclophotocoagulation. Cyclodestructive procedures have traditionally been used for refractory glaucomas, and success rates have been reported in the range of 34% to 94%. They have been associated with a subsequent decrease of visual acuity and, rarely, cases of sympathetic ophthalmia. Disadvantages of cyclodestructive procedures include postoperative inflammation, IOP spike, and the frequent need for repeat treatment weeks or months later. Compared with cyclocryotherapy, laser cyclophotocoagulation causes less postoperative pain and inflammation. Therefore, cyclocryotherapy is now rarely used. Laser cyclodestructive procedures have advantages over filtration surgery that include technical ease and reduced postoperative care.

Endoscopic cyclophotocoagulation may be combined with cataract surgery or tube-shunt surgery.

Follow-up Evaluation

Guidelines for follow-up of patients with POAG are summarized in Table 6 in the original guideline document. These recommendations apply to ongoing glaucoma management and not to visits for other purposes. Follow-up evaluation includes examination as well as optic nerve head and visual field assessment as indicated.

History

The following interval history should be elicited at POAG follow-up visits

• Interval ocular history [A:III]
• Interval systemic medical history [B:III]
• Side effects of ocular medications [A:III]
• Frequency and time of last IOP-lowering medications and review of use of medications [B:III]

Ophthalmic Examination

The following components of the ophthalmic examination should be performed at POAG follow-up visits:

• Visual acuity measurement [A:III]
• Slit-lamp biomicroscopy [A:III]
• IOP measurement [A:III]

Based on the understanding of the effect of CCT on IOP measurements, measurement of CCT should be repeated after any event (e.g., refractive surgery) that may alter CCT. [A:II]

Gonioscopy

Gonioscopy is indicated when there is a suspicion of an angle-closure component, anterior chamber shallowing or anterior chamber angle abnormalities, or if there is an unexplained change in IOP. [A:III] Gonioscopy may also be performed periodically (e.g., 1 to 5 years). [A:III]

Optic Nerve Head and Visual Field Evaluation [A:III]

Optic nerve head evaluation and documentation by imaging, photography, or drawing and visual field evaluation should be performed at the recommended intervals listed in Table 6 of the original guideline document.

Within each of the recommended intervals, factors that determine frequency of evaluations include the severity of damage (mild, moderate, severe, with more frequent evaluations for more severe disease), the rate of progression, the extent to which the IOP exceeds the target pressure, and the number and significance of other risk factors for damage to the optic nerve. [A:III] In certain cases, follow-up visual field testing may be required more frequently than the recommended intervals (e.g., a second test to establish a baseline for future comparisons, to clarify a suspicious test result, or to overcome an apparent testing artifact).

Risk Factors for Progression

The risk factors for progression in eyes already diagnosed with OAG are related to the level of IOP and factors independent of IOP:

• Intraocular pressure
• Beta-zone peripapillary atrophy
• Older age
• Disc hemorrhage
• Larger cup-to-disc ratio or smaller optic nerve rim area
• Thinner central cornea

Damage in one eye is associated with an increased risk of future damage in the other eye.

Adjustment of Therapy

The indications for adjusting therapy are as follows: [A:III]

• Target IOP is not achieved and the benefits of a change in therapy outweigh the risks for the patient
• A patient has progressive optic nerve damage despite achieving the target IOP.
• The patient is intolerant of the prescribed medical regimen.
• The patient does not adhere to the prescribed medical regimen because of cost or other issues.
• Contraindications to individual medicines develop.
• Stable optic nerve status and low IOP occurs for a prolonged period in a patient on glaucoma medications. Under these circumstances, a carefully monitored attempt to reduce the medical regimen may be appropriate.

Downward adjustment of target pressure should be considered in the face of progressive optic disc or visual field change (Vogel et al., 1992; Stewart et al., 1993; Coleman & Caprioli, 2009; Damji et al., 2003; European Glaucoma Society, 2008). [A:III]

Upward adjustment of target pressure can be considered if the patient has been stable and if the patient either requires (because of side effects) or desires less medication. A follow-up visit in 2 to 8 weeks may help to assess the response and side effects from washout of the old medication or onset of maximum effect of the new medication.

Provider and Setting

The performance of certain diagnostic procedures (e.g., tonometry, pachymetry, perimetry, optic disc imaging, and photography) may be delegated to appropriately trained and supervised personnel. However, the interpretation of results and medical and surgical management of disease require the medical training, clinical judgment, and experience of the ophthalmologist.

Most diagnostic and therapeutic procedures can be safely undertaken on an outpatient basis. In some instances, however, hospitalization may be required. This includes, for example, patients who have special medical or social needs.

Counseling/Referral

Patients should be educated about the disease process, the rationale and goals of intervention, the status of their condition, and the relative benefits and risks of alternative interventions so that they can participate meaningfully in developing an appropriate plan of action. [A:III] Patients should be encouraged to alert their ophthalmologists to physical or emotional changes that occur when taking glaucoma medications. [A:III]

Glaucoma affects the patient's visual and health-related quality of life in many ways; this includes employment issues (e.g., fear of loss of job and insurance from diminished ability to read and drive), social issues (e.g., fear of negative impact on relationships and sexuality), and loss of independence and activities that require good visual acuity (e.g., sports and other hobbies). The ophthalmologist should be sensitive to these problems and provide support and encouragement. [A:III] Some patients may find peer-support groups or counseling helpful.

Patients considering keratorefractive surgery should be informed about the possible impact laser vision correction has on reducing contrast sensitivity, altering visual field testing results, and decreasing the accuracy of IOP measurements. [A:III] During the conduct of LASIK the IOP will briefly increase from the effect of the suction ring to make the eye rigid during creation of the superficial flap. This effect may cause additional damage in patients whose optic nerves already have advanced damage. Therefore, LASIK may be relatively contraindicated in such individuals, but photorefractive keratectomy may be possible. In addition, postoperative fluid may develop in the corneal flap-stromal interface and lead to temporary underestimation of the applanation IOP in patients treated aggressively with topical corticosteroids to resolve interface inflammation, who may actually have an undetected, corticosteroid-induced elevation of IOP. Conversely, corticosteroid-induced IOP elevation may cause interface fluid that mimics interface inflammation and leads to IOP underestimation. Patients with glaucomatous optic neuropathy considering implantation of a multifocal intraocular lens should be informed of the risk of reduced contrast sensitivity. [A:III] It is important to establish preoperative and baseline documentation of optic nerve head status and visual field to facilitate subsequent glaucoma management.

If the diagnosis or management of POAG is in question or if the condition is refractory to treatment, consultation with or referral to an ophthalmologist with special training or experience in managing glaucoma should be considered. Patients with substantial visual impairment or blindness can be referred for and encouraged to use appropriate visual rehabilitation and social services. [A:III]

Definitions:

Ratings of Importance to Care Process

Level A, defined as most important

Level B, defined as moderately important

Level C, defined as relevant, but not critical

Ratings of Strength of Evidence

Level I includes evidence obtained from at least one properly conducted, well-designed, randomized controlled trial. It could include meta-analyses of randomized controlled trials.

Level II includes evidence obtained from the following:

• Well-designed controlled trials without randomization
• Well-designed cohort or case-control analytic studies, preferably from more than one center
• Multiple-time series with or without the intervention

Level III includes evidence obtained from one of the following:

• Descriptive studies
• Case reports
• Reports of expert committees/organizations (e.g., Preferred Practice Pattern [PPP] panel consensus with external peer review)

A clinical algorithm for the treatment of patients with primary open-angle glaucoma is provided in Appendix 3 of the original guideline document.

The type of supporting evidence is identified and graded for each recommendation (see "Major Recommendations" field).

Appropriate identification and management of a patient with primary open-angle glaucoma (POAG)

Refer to Table 4 in the original guideline document for information on contraindications to glaucoma medications.

An implementation strategy was not provided.

Not applicable: The guideline was not adapted from another source.

American Academy of Ophthalmology (AAO)

Glaucoma Panel; Preferred Practice Patterns Committee

Glaucoma Panel Members: Bruce E. Prum, Jr., MD, Chair; David S. Friedman, MD, MPH, PhD, American Glaucoma Society Representative; Steven J. Gedde, MD; Leon W. Herndon, MD; Young H. Kwon, MD, PhD; Michele C. Lim, MD; Lisa F. Rosenberg, MD; Rohit Varma, MD, MPH, Methodologist

Preferred Practice Patterns Committee Members: Christopher J. Rapuano, MD, Chair; David F. Chang, MD; Emily Y. Chew, MD; Robert S. Feder, MD; Stephen D. McLeod, MD; Bruce E. Prum, Jr., MD; R. Michael Siatkowski, MD; David C. Musch, PhD, MPH, Methodologist

The panel and committee members have disclosed the following financial relationships occurring from January 2009 to September 2010:

David F. Chang, MD: Advanced Medical Optics – Consultant/Advisor; Alcon Laboratories, Inc. – Consultant/Advisor; Allergan, Inc. – Lecture fees; Calhoun Vision, Inc. – Consultant/Advisor, Equity owner; Eyemaginations, Inc. – Consultant/Advisor, Patent/Royalty; Ista Pharmaceuticals – Consultant/Advisor, Grant support; LensAR – Consultant/Advisor; Hoya – Consultant/Advisor; Peak Surgical – Consultant/Advisor; Revital Vision – Equity owner; SLACK, Inc. – Patent/Royalty; Transcend Medical – Consultant/Advisor; Visiogen, Inc. – Consultant/Advisor, Equity owner

Emily Y. Chew, MD: No financial relationships to disclose.

Robert S. Feder, MD: No financial relationships to disclose.

David S. Friedman, MD, MPH, PhD: Alcon Laboratories, Inc. – Grant support; NiCox – Consultant/Advisor; Novartis Pharmaceuticals Corp. – Consultant/Advisor; ORBIS International – Consultant/Advisor; Pfizer, Inc. – Consultant/Advisor, Lecture fees, Grant support; Promedior – Consultant/Advisor; Zeiss Meditec – Grant support

Steven J. Gedde, MD: Lumenis, Inc. – Lecture fees

Leon W. Herndon, MD: Alcon Laboratories, Inc. – Consultant/Advisor, Lecture fees; Allergan, Inc. – Lecture fees; iScience – Lecture fees; Ista Pharmaceuticals – Consultant/Advisor, Lecture fees; Merck & Co., Inc. – Lecture fees; Optonol, Ltd. – Lecture fees; Pfizer, Inc. – Lecture fees; Reichert, Inc. – Lecture fees

Young H. Kwon, MD, PhD: Allergan, Inc. – Consultant/Advisor; Free Educational Publications, Inc. – Equity owner; Pfizer, Inc. – Consultant/Advisor

Michele C. Lim, MD: No financial relationships to disclose.

Stephen D. McLeod, MD: Abbott Medical Optics – Consultant/Advisor, Equity owner; Visiogen, Inc. – Consultant/Advisor, Equity owner

David C. Musch, PhD, MPH: Glaukos Corp. – Consultant/Advisor; MacuSight, Inc. – Consultant/Advisor; National Eye Institute – Grant support; NeoVista, Inc. – Consultant/Advisor; Neurotech USA, Inc. – Consultant/Advisor; OPKO Health, Inc. – Consultant/Advisor; Oraya Therapeutics, Inc. – Consultant/Advisor; Pfizer Ophthalmics – Grant support; Washington University – Grant support

Bruce E. Prum Jr., MD: Alcon Laboratories, Inc. – Grant support; Allergan, Inc. – Consultant/Advisor

Christopher J. Rapuano, MD: Alcon Laboratories, Inc. – Lecture fees; Allergan, Inc. – Consultant/Advisor, Lecture fees; Bausch & Lomb – Lecture fees; Inspire – Lecture fees; EyeGate Pharma – Consultant/Advisor; Inspire – Lecture fees; Rapid Pathogen Screening – Equity owner; Vistakon Johnson & Johnson Visioncare, Inc. – Lecture fees

Lisa F. Rosenberg, MD: No financial relationships to disclose.

R. Michael Siatkowski, MD: National Eye Institute – Grant support

Rohit Varma, MD, MPH: Alcon Laboratories, Inc. – Consultant/Advisor, Lecture fees; Allergan, Inc. – Consultant/Advisor, Grant support; Aquesys – Consultant/Advisor, Equity owner, Grant support; Bausch & Lomb Surgical – Consultant/Advisor; Genentech, Inc. – Consultant/Advisor, Grant support; Merck & Co., Inc. – Consultant/Advisor; National Eye Institute – Grant support; Optovue – Grant support; Pfizer, Inc. – Consultant/Advisor, Lecture fees, Grant support; Replenish, Inc. – Consultant/Advisor, Equity owner, Grant support

This is the current release of the guideline.

This guideline updates a previous version: Glaucoma Panel, Preferred Practice Patterns Committee. Primary open-angle glaucoma. San Francisco (CA): American Academy of Ophthalmology (AAO); 2005. 36 p. (Preferred practice pattern).

All Preferred Practice Patterns (PPPs) are reviewed by their parent panel annually or earlier if developments warrant and updated accordingly. To ensure that all PPPs are current, each is valid for 5 years from the "approved by" date unless superseded by a revision.

Electronic copies: Available from the American Academy of Ophthalmology (AAO) Web site .

Print copies: Available from American Academy of Ophthalmology, P.O. Box 7424, San Francisco, CA 94120-7424; telephone, (415) 561-8540.

The following is available:

• Summary benchmarks for preferred practice patterns. San Francisco (CA): American Academy of Ophthalmology; 2010 Oct. 3 p. Available in Portable Document Format (PDF) from the American Academy of Ophthalmology (AAO) Web site .

Print copies: Available from American Academy of Ophthalmology, P.O. Box 7424, San Francisco, CA 94120-7424; telephone, (415) 561-8540.

The following is also available:

• Digital-eyes ophthalmic animations for patients subscription. Slide presentation. San Francisco (CA): American Academy of Ophthalmology; 2010. Available for purchase in English and Spanish from the American Academy of Ophthalmology (AAO) Web site .

The following are available:

• Eyedrops. Patient education brochure. San Francisco (CA): American Academy of Ophthalmology; 2010. 1 p. Available for purchase from the American Academy of Ophthalmology (AAO) Web site .
• Glaucoma. Patient education booklet. San Francisco (CA): American Academy of Ophthalmology; 2010. 1 p. Available for purchase from the American Academy of Ophthalmology (AAO) Web site .
• Glaucoma. Patient education brochure. San Francisco (CA): American Academy of Ophthalmology; 2010. 1 p. Available for purchase in English and Spanish from the American Academy of Ophthalmology (AAO) Web site .
• Surgery for open-angle glaucoma brochure. Patient education brochure. San Francisco (CA): American Academy of Ophthalmology; 2010. 1 p. Available for purchase from the American Academy of Ophthalmology (AAO) Web site .

Also, there are a variety of other patient education products available for purchase in English and Spanish from the American Academy of Ophthalmology (AAO) Web site .

Please note: This patient information is intended to provide health professionals with information to share with their patients to help them better understand their health and their diagnosed disorders. By providing access to this patient information, it is not the intention of NGC to provide specific medical advice for particular patients. Rather we urge patients and their representatives to review this material and then to consult with a licensed health professional for evaluation of treatment options suitable for them as well as for diagnosis and answers to their personal medical questions. This patient information has been derived and prepared from a guideline for health care professionals included on NGC by the authors or publishers of that original guideline. The patient information is not reviewed by NGC to establish whether or not it accurately reflects the original guideline's content.

This summary was completed by ECRI on November 20, 2000. The information was verified by the guideline developer on December 20, 2000. This summary was updated on March 12, 2003 and again on April 9, 2004. The updated information was verified by the guideline developer on May 20, 2004. This NGC summary was updated by ECRI on January 9, 2006. The updated information was verified by the guideline developer on February 9, 2006. This NGC summary was updated by ECRI Institute on February 16, 2011.

This NGC summary is based on the original guideline, which is subject to the guideline developer's copyright restrictions. Information about the content, ordering, and copyright permissions can be obtained by calling the American Academy of Ophthalmology at (415) 561-8500.