Canadian Ophthalmological
Society
Evidence-based Clinical Practice
Guidelines for the Management of
Glaucoma in the Adult Eye
Canadian Ophthalmological Society
Glaucoma Clinical Practice Guideline
Expert Committee
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Paul E. Rafuse, MD PhD FRCSC (Chair), Halifax, NS
Yvonne M. Buys, MD FRCSC, Toronto, ON
Karim F. Damji, MD MBA FRCSC, Edmonton, AB
Paul Harasymowycz, MD FRCSC, Montreal, QC
Caroline Lajoie, MD MSc FRCSC DABO, Quebec City, QC
Frederick S. Mikelberg, MD FRCSC, Vancouver, BC
Paul H. Murphy, MD FRCSC, Saskatoon, SK
Marcelo Nicolela, MD FRCSC, Halifax, NS
David P. Tingey, MD FRCSC, London, ON
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Funding
• Funding for the development of this guideline was provided by
the Canadian Ophthalmological Society and the following
sponsors, in the form of unrestricted educational grants:
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Abbott Medical Optics
Alcon Canada Inc.
Allergan Canada Inc.
Pfizer Canada Inc.
Novartis Canada Inc.
• Neither industry nor government was involved in the decision
to publish guidelines, in the choice of guideline, or in any
aspect of guideline development.
• Clinical Practice Guideline Expert Committee members were
volunteers, and received no remuneration or honoraria for
their time or work.
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Objectives
These guidelines are intended to:
• Provide guidance to Canadian ophthalmologists on the
management of glaucoma in adults.
• Advise users regarding patterns of clinical practice.
These guidelines are not intended to:
• Restrict innovation.
• Provide a “cookbook” approach to medicine or to be a
replacement for clinical judgment.
• Be used as a legal resource, as their general nature cannot
provide individualized guidance for all patients in all
circumstances.
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Methods
Methods
• Recommendations were formulated using the best available
evidence with consideration of the health benefits, risks and side
effects of interventions.
• References used to support recommendations were assigned a
level of evidence based upon the criteria used by other national
organizations.1,2
• In the absence of direct evidence, recommendations were written to
reflect unanimous consensus of the expert committee.
• These guidelines were developed in accordance with the Canadian
Medical Association Handbook on Clinical Practice Guidelines3 and
the AGREE Instrument.4
1. Clinical Practice Guideline Expert Committee. Can
J Diabetes 2008;32(suppl 1):S1–S201. 2. Canadian
Hypertension Education Program. Available at:
http://hypertension.ca. 3. Davis D, et al. Ottawa, ON;
Canadian Medical Association; 2007. 4. AGREE
Canadian Ophthalmological Society evidence-based clinical
Collaboration. Available at:
practice guidelines for the management of glaucoma in the
http://agreecollaboration.org.
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Criteria for assigning levels of
evidence to the published studies
Level
Criteria
Studies of diagnosis
Level 1
i.
Level 2
Independent interpretation of test results (without knowledge
of the result of the diagnostic or gold standard)
ii. Independent interpretation of the diagnostic standard (without
knowledge of the test result)
iii. Selection of people suspected (but not known) to have the
disorder
iv. Reproducible description of both the test and diagnostic
standard
v. At least 50 patients with and 50 patients without the disorder
Meets 4 of the Level 1 criteria
Level 3
Meets 3 of the Level 1 criteria
Level 4
Meets 1 or 2 of the Level 1 criteria
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Criteria for assigning levels of
evidence to the published studies (cont’d)
Level
Criteria
Studies of treatment and prevention
Level 1A
Level 3
Systematic overview or meta-analysis of high-quality
randomized, controlled trials
Appropriately designed randomized, controlled trial with
adequate power to answer the question posed by the
investigators
Nonrandomized clinical trial or cohort study with
indisputable results
Randomized, controlled trial or systematic overview that
does not meet Level 1 criteria
Nonrandomized clinical trial or cohort study
Level 4
Other
Level 1B
Level 2
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Criteria for assigning levels of
evidence to the published studies (cont’d)
Level
Criteria
Studies of prognosis
Level 1
i.
Level 2
Inception cohort of patients with the condition of
interest, but free of the outcome of interest
ii. Reproducible inclusion/exclusion criteria
iii. Follow-up of at least 80% of subjects
iv. Statistical adjustment for extraneous prognostic factors
(confounders)
v. Reproducible description of outcome measures
Meets criterion (i) above, plus 3 of the other 4 criteria
Level 3
Meets criterion (i) above, plus 2 of the other criteria
Level 4
Meets criterion (i) above, plus 1 of the other criteria
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Definition & Classification
Definitions
Ocular hypertension
• IOP increases when there is obstruction to aqueous
outflow. This occurs when:
– the iridocorneal drainage angle is closed due to apposition of the
trabecular meshwork and iris root (closed-angle),
– there is obstruction to outflow through the drainage pathways of
an open angle, or
– when there is an obstruction to the venous drainage of the eye.
Closed-angle glaucoma
• Closed-angle glaucoma develops if the high IOP causes
glaucomatous damage to the optic disc.
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Definitions (cont’d)
Open-angle glaucoma
• Open-angle glaucoma occurs if damage to the disc is present
in the face of an open angle.
Idiopathic or primary glaucomas
• These are open-angle or closed-angle glaucomas with no
identifiable cause.
Secondary angle closure glaucomas
• These involve angle closure or elevated IOP with an
identifiable cause.
Gonioscopy is required to determine if the angle is closed,
open or abnormal.1
1. Alwards WLM. Gonioscopy.org.
Available at: http://www.gonioscopy.org/.
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Classification
• The most useful way to classify the glaucomas is according to
anatomy and pathogenesis.
• Elevated IOP is no longer part of the modern definition of
glaucoma, but is associated with:
– the development of glaucoma,1
– the prevalence of the disease in a population,2 and
– the progression of the disease.3
• Lowering IOP therapeutically has been shown to reduce
progression of VF loss in patients with glaucoma.3
• Clarifying the causes of IOP elevation is an important part of
classifying and understanding the disease.
Canadian Ophthalmological Society evidence-based clinical
1. Gordon MA, et al. Arch Ophthalmol 2002;120:714–20.
practice guidelines for the management of glaucoma in the
2. Dielemans I, et al. Ophthalmol 1994;101:1851–5.
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
3. AGIS Investigators. Am J Ophthalmol 2000;130:429–40.
Gonioscopy — open and
closed angles
Recommendation
Gonioscopy should be performed to determine if
an elevated IOP is associated with an iridocorneal
angle that is open, closed or structurally abnormal.
Classification of the glaucoma on the basis of the
appearance of the angle on gonioscopy will guide
appropriate management [Consensus].
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Primary open-angle
glaucoma suspects
• An individual who is found on history and clinical
examination to have:
– optic disc features suspicious for GON,
– suggestive VF defects, or
– a constellation of risk factors for POAG that confer a
heightened probability of developing the disease.
• People with elevated IOP (>21 mm Hg), but with no
evidence of GON or glaucomatous VF damage,
would qualify as POAG suspects on the basis of
having ocular hypertension.
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Gonioscopy — secondary
glaucomas
Recommendation
As many secondary glaucomas (e.g. PXF,
neovascularisation, uveitis, and surgical
trauma) can occur with angles that are either
open or closed, careful gonioscopy is
required to clarify the pathogenesis and
management options [Consensus].
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Mixed and Multiplemechanism Glaucomas
Multiple-mechanism glaucomas
• Multiple-mechanism glaucomas occur when the
cause of the elevated IOP is multifactorial with a
number of possible influences of either, or both,
open- and closed-angle mechanisms.
• Examples include:
– A patient with iritis, an elevated IOP, and an additional
IOP response to the corticosteroid treatment.
– A patient with known PXF glaucoma, or POAG, who
suffers a central retinal vein occlusion and
subsequent neovascularisation of the anterior
segment.
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Epidemiology and Burden
of Blindness
Epidemiology and burden
of blindness
• Glaucoma is the second leading cause (after cataract) of
blindness worldwide, and is the number one cause of
irreversible vision loss.1
• The prevalence of the various types of glaucoma follows
racial and ethnic boundaries.
• There may be approximately 409 0002 people with
glaucoma in Canada.
• Due to the asymptomatic nature of chronic glaucoma, up
to 50% of those with glaucoma in the industrialized world
are unaware of it and are not receiving care.3,4
1. Resnikoff S, et al. 2002. Bull WHO 2004;82:844–51.
2. Perruccio AV, et al. Can J Ophthalmol 2007;42:219–26.
3. Sommer A, et al. Arch Ophthalmol 1991;109:1090–5.
4. Mitchell P, et al. Ophthalmology 1996;103:1661–9.
Canadian Ophthalmological Society evidence-based clinical
practice guidelines for the management of glaucoma in the
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.
Screening for Glaucoma
Screening for glaucoma
Recommendation
It is recommended that population screening can
be considered for high-risk populations. Screening
should include both structural and functional
measures of the disease. Screening for IOP alone
should be avoided since it has low sensitivity, low
specificity, and poor predictive value for the
detection of glaucomas [Level 11–3].
Canadian Ophthalmological Society evidence-based clinical
1. Dielemans I, et al. Ophthalmol 1994;101:1851–5.
2. Sommer A, et al. Arch Ophthalmol 1991;109:1090–5. practice guidelines for the management of glaucoma in the
3. Mitchell P, et al. Ophthalmology 1996;103:1661–9.
adult eye. Can J Ophthalmol 2009;44(Suppl 1):S1S93.