Diagnosis of Primary Open Angle Glaucoma
edited by:R.N. Weinreb, D.F. Garway-Heath, C. Leung, F.A.
Medeiros and J. Liebmann
The goal of this consensus is to provide a foundation for diagnosing and managing
primary open-angle glaucoma and how it can be best done in clinical practice. Identification
of those areas for which we have little evidence and, therefore, the need for additional
research always is a high priority. We hope that this consensus report will serve
as a benchmark of our understanding. However, this consensus report is intended
to be fluid. It is expected that it will be revised and improved with the emergence
of new evidence
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Robert N. Weinreb
Consensus Initiative Chair
World Glaucoma Association
Summary Consensus Points
Section 1 - Structure
- Clinical evaluation and documentation of the optic nerve head is essential
for the diagnosis and the monitoring of glaucoma.
- Clinical diagnosis of glaucoma is predicated on the detection of a thinned
retinal nerve fiber layer (RNFL) and narrowed neuroretinal rim.
These features often are accompanied by deformation of the optic nerve head
(ONH) (cupping). These features often appear first in the supero- or inferotemporal
quadrants. Although these features are characteristic of POAG, it is important
to exclude non-glaucomatous optic neuropathies.
- Detecting progressive glaucomatous RNFL thinning and neuroretinal rim narrowing
are the best currently available gold standards for glaucoma diagnosis.
Comment: Disease-related damage should be differentiated from age-related
- The diagnosis of glaucoma does not always require the detection of visual
field defects with perimetry.
Comments: Perimetric defects that
correspond to structural findings increase the likelihood of glaucoma. Perimetry
is indispensable for documentation and monitoring of functional decline in glaucoma.
- Assessment of the color and the configuration (size and shape) of the neuroret-
inal rim is important to differentiate glaucomatous from non-glaucomatous optic
Comment: A pale rim suggests non-glaucomatous optic
- Photography is effective to document glaucomatous optic disc appearance
and nerve fiber layer damage.
Comments: Photography is particularly
useful for detecting and documenting optic disc hemorrhage and rim color. Stereophotography
is particularly useful for documenting optic disc topography.
- Imaging technologies including optical coherence tomography (OCT), confocal
scanning laser ophthalmoscopy (CSLO) and scanning laser polarimetry (SLP) provide
an objective and quantitative approach to detect and monitor glaucoma.
- OCT may be the best currently available digital imaging instrument for detecting
and tracking optic nerve structural damage in glaucoma.
- RNFL thickness is the most clinically helpful parameter of the ones currently
available with OCT.
Comments: Macular RGC loss in glaucoma also
can be detected by OCT. RNFL thickness and macular RGC loss are complementary.
Pitfalls of OCT such as artifacts and false segmentation should be considered
when using OCT. GCIPL thickness (macula): The macula has the highest density
- It is difficult in myopic eyes to differentiate those with and without glaucoma.
Comments: In myopic eyes, documented progressive optic neuropathy
can be used to make the differential diagnosis of glaucoma. Reference databases
do not currently include highly myopic eyes and, therefore, are not appropriate
for diagnosing RNFL damage in them.
Section 2- Vision function
- Functional testing is essential for the evaluation, staging and monitoring
Comment: Standard automated perimetry (SAP) is the
reference standard for all functional testing.
- Clinical decisions should be made based on reliable visual field tests.
Comments: Visual field defects should be reproducible and/or should
be consistent with the location of the optic nerve defects. The most important
reliability criterion is the false positive rate.
- In the presence of glaucomatous optic neuropathy, a Glaucoma Hemifield Test
(GHT) ‘outside normal limits’ in a reliable visual field indicates that glauco-
matous visual field loss is present.
Comment: For instruments not
calculating a GHT, an abnormal (P &st; 5%) pattern standard deviation (PSD)
or square-root-loss variance (sLV) likely have similar diagnostic value.
- When glaucomatous optic neuropathy (GON) is suspected, a GHT criterion of
‘outside normal limits’ or ‘borderline’ in a reliable visual field increases
the probability that an eye has glaucoma.
Comment: The level of
probability for glaucoma depends on the presence and magnitude of other risk
factors for glaucoma (such as raised intraocular pressure) and the quality of
evidence that there is no GON.
- Before a visual field defect can be confirmed as glaucomatous, retinal and
non-glaucomatous optic disc conditions should be excluded by a careful examination
of the retina and optic disc.
Comment: If the pattern of visual
field loss suggests a neurological origin, or if there is incongruity between
the pattern of visual field loss and optic disc and retinal nerve fiber layer
appearance, then further investigation is warranted (e.g., color vision
- Standard white-on-white automated perimetry (SAP), with a fixed testing
matrix covering at least the central 24 degrees, is preferred for the diagnosis
of glaucomatous visual field loss.
Comments: Goldmann size III
stimuli are conventionally used in most automated perimeters in clinical practice
for glaucoma diagnosis. For more severe cases size V, increases the dynamic
range and reduces variability of test results. Using the 10-2 strategy, in addition
to the conventional 24-2 Humphrey grid, can improve the detection of central
- Threshold algorithms are preferred over supra-threshold algorithms for glaucoma
Comment: Supra-threshold algorithms can be helpful in
cases of unreliable results from threshold testing algorithms.
- Neither short-wavelength automated perimetry (SWAP) nor frequency doubling
technology (FDT) perimetry have superior diagnostic precision to SAP.
Comments: Patients should be followed consistently with same visual
function test and ideally one with statistical support for recognizing change.
The more diagnostic tests that are performed, the more likely it is that one
will be ‘outside normal limits’, therefore increasing the number of false positive
- Patients who are at risk for glaucoma and have normal standard automated
perimetry (SAP) should have their visual function monitored to detect deteri-
oration and hence establish a glaucoma diagnosis.
Comment: The earliest
evidence for glaucoma may be functional or structural. Therefore, both should
be measured to ensure that the onset of glaucoma damage is not overlooked.
- Deterioration may be first detected by the glaucoma hemifield test (GHT)
(or summary parameters) or by trend analysis of measurements over time. Which
analysis is most sensitive varies between patients and so both should be done.
Comments: Progressive functional loss identified by SAP may be a generalized
reduction in visual field sensitivity alone, or focal loss alone, or a combination
of both. If trend analysis indicates a change in VFI, MD or mean defect, then
one needs to exclude media opacity (e.g., cataract).
- There only is weak evidence for the use of functional measurements other
than SAP to detect the earliest signs of deterioration.
- There is a limited role for ERG testing in the routine diagnosis and management
Comment: PERG and PhNR testing are not substitutes
for standard automated perimetry (SAP), nor are they substitutes for optical
coherence tomography (OCT) imaging.
- The classification of glaucomatous functional damage in stages of increasing
severity is a useful tool in the management of patients affected with chronic
Comment: Staging provides a summary metric of disease
severity which may guide treatment decisions.
- While staging systems may be clinically useful, no current staging system
shows all the information present in a visual field printout.
For instance, staging systems do not identify the location of damage.
- POAG-related functional impairment affects patients’ ability to perform
daily activities and also their well-being (vision-related quality of life).
Worse vision-related quality of life is associated with greater severity of
Comment: Vision-related quality of life may be assessed
with question- naires, by performance tasks (e.g., reading), event
monitoring (e.g., falls) and measures of behavior (e.g., GPS
- Understanding how glaucoma and glaucoma treatment affects patients’ quality
of life, and how this varies across the severity continuum, can have practical
value in the clinic. It can inform treatment choices and communica- tion to
patients of the implications of disease worsening.
- The impact of glaucomatous visual field loss on vision-related function
and quality of life depends on the location of the defect in the field of vision
and the task involved.
Comment: risk of falling, eye-hand coordination
and mobility may be most affected by loss in the inferior hemifield, whereas
reading may be more affected by superior hemifield loss.
- Aspects of glaucoma other than visual field loss, such as reduced central
contrast sensitivity and acuity (in more advanced disease), may affect vision-related
function and quality of life.
Comment: Contrast sensitivity is
more strongly associated with specific aspects of reading performance than visual
Section 3 - Structure and function
- In glaucoma, there is a continuous relationship between standard structural
and functional (dB for visual field) measurements, which appears nonlinear with
current methods of testing and conventional scaling of metrics.
When both are transformed into linear scales, then a linear relation- ship between
structure and function can be observed.
- Current structural and functional measurement methods show considerable
- Visual field test locations are spatially related to regions on the optic
nerve head, peripapillary retina and macular area.
these spatial relationships can be useful for the diagnosis of glaucoma.
- With current technology, detection of structural defects generally precedes
detectable functional defects in glaucoma patients while functional defects
can precede structural defects in some patients.
tests based on the comparison to the normative data tend to show a statistically
significant glaucomatous change earlier compared to the functional tests because
of a greater variability in functional tests.
- The likelihood of the diagnosis of glaucoma is increased through corrobora-
tion of abnormal structural and functional tests.
likelihood of the diagnosis of glaucoma is increased further if there is progressive
change or if additional risk factors are present, such as raised intraocular
- When available, OCT (or an alternative imaging modality) and disc photographs
with acceptable quality at baseline should be performed, against which accurate
detection of change can be made.
Comments: Disc photography is
a useful adjunct for detecting hemorrhages and pallor, and also for assessing
change compared with future clinical exam- inations. Disc hemorrhages can only
be seen on clinical examinations and disc photographs.
- As yet there is no widely-accepted method of combining the results of structural
and functional tests.
Comment: Several proposed methods for combining
structural and/or functional measurements offer advantages over traditional
parameters and continue to be investigated.
- Physicians should be aware of false-positive tests and over-diagnosing glaucoma,
which are more likely when using a large number of diagnostic tests.
Comment: Although using multiple parameters may increase overall diagnostic
sensitivity, the chance will also increase of falsely labeling a change significant.
Section 4 - Risk factors (ocular)
- Although POAG may develop at any IOP, there is strong evidence supporting
higher mean intraocular pressure during follow-up as a risk factor for development
and progression of glaucomatous damage.
Comments: There is insufficient
evidence and further studies are needed to elucidate which IOP parameter(s)
(mean, peak and/or fluctuation, area under IOP curve, etc.) is most important
in determining risk of glaucoma development or progression. There is insufficient
evidence implicating IOP fluctuations as an independent risk factor for glaucoma
development or progression.
- Low ocular perfusion pressure (OPP) (the difference between systemic blood
pressure and intraocular pressure) is associated with increased prevalence of
open-angle glaucoma in cross-sectional studies.
Comments: The value
of OPP monitoring in daily clinical practice is not established. Due to the
intrinsic relationship between OPP and IOP, it is difficult to establish an
independent contribution of OPP as a risk factor for the development of glaucoma.
- There is insufficient evidence supporting the role of provocative tests,
such as the water-drinking test, as providing independent contribution to assess
risk of glaucoma development and progression.
longitudinal studies are necessary to clarify whether the water-drinking provocative
test can provide additional information over office-based IOP measurements in
establishing risk of glaucoma development or progression.
- There is strong evidence supporting the role of central corneal thickness
(CCT) as an important predictive factor for glaucoma development in ocular hypertensives
and glaucoma suspects. Baseline CCT measurements should be obtained in patients
suspected of having glaucoma.
Comments: Algorithms to correct IOP
based on CCT measurements are not recommended for routine use in clinical practice.
There is insufficient evidence to conclude whether or not CCT is a true independent
risk factor for glaucoma development or progression, or whether its effect is
related to a tonometric artifact. There is no evidence that serial CCT measurements
have value in clinical evaluation glaucoma.
- There is strong evidence implicating lower corneal hysteresis as a risk
factor for glaucoma development and progression.
is insufficient evidence about the mechanisms by which corneal hysteresis is
associated with risk of glaucoma progression.
- Existing evidence suggests that individuals with myopia have an increased
risk of developing open angle glaucoma, with the risk being greater for people
with high myopia.
Comments: Diagnosis of glaucoma among myopic
eyes can be challenging. Confirmed evidence of glaucomatous progression from
a well-defined baseline is important for a correct diagnosis in many myopic
- Disc hemorrhage is associated with increased risk of developing glaucoma
and it is a marker for glaucomatous progression.
of treatment escalation or closer follow-up should be given for patients presenting
with optic disc hemorrhages.
- Predictive models (risk calculators) may provide objective assessment of
individual risk and their use should be considered in patients suspected of
Comment: Current validated risk calculators apply
only to OHT patients. Moreover, they do not include all known risk factors.
Section 5 - Risk assessment
- Primary open-angle glaucoma (POAG) occurs at all ages, and the incidence
and prevalence accelerates with age.
- Populations with the highest incidence and prevalence of POAG have African
Comment: Due to the earlier age of disease onset, the
average duration of POAG may be greatest in individuals of African ancestry.
- Hispanics may have higher incidence and prevalence of POAG than individuals
of European ancestry (non-Hispanic whites).
- Older age is a risk factor for glaucoma onset and progression.
- Although an increased prevalence of POAG in men has been reported, there
is not enough evidence to support an association of POAG risk with male gender.
- Lower socioeconomic status may be associated with later presentation of
- First-degree relatives of POAG patients are at higher risk for glaucoma.
- Although genetic association studies have revealed multiple associated loci
for POAG, there is little value for routine genetic testing to diagnose or predict
the development of glaucoma at the current time.
- There is consistent, but weak, positive association between diastolic blood
pressure and IOP and between systolic blood pressure and IOP in popula- tion-based
- Lower blood pressure (BP) and ocular perfusion pressure are associated with
higher glaucoma prevalence and incidence across all racial groups.
It is not known whether ocular perfusion pressure (OPP ) is an independent risk
factor for glaucoma due to the fact that IOP is intrinsically used in the calculation
as performed with current methods.
- The relationships between diastolic blood pressure, systolic blood pressure,
systemic hypotension or systemic hypertension, and POAG are inconsistent.
- The relationship between treatment of systemic hypertension and the development
of POAG remains unclear.
Comment: There are data suggesting that
some patients being treated for systemic hypertension may be at greater risk
for development of POAG.
- The role of nocturnal systemic hypotension in the development of glaucoma
is not known.
- The evidence that obstructive sleep apnea is a risk factor for open-angle
glaucoma (OAG) is weak and warrants further study.
- Diabetes mellitus likely increases the risk for glaucoma onset.
- There is insufficient evidence to determine if thyroid disease is associated
- Although there is some evidence that reduction of estrogen production in
post-menopausal women increases glaucoma risk, there is insufficient evidence
for hormonal replacement.
Section 6 - Screening
- Glaucoma is the leading cause of irreversible blindness worldwide.
Comment: In some countries, as many as 90% of glaucoma patients remain
- Screening everyone for glaucoma is an ideal proposition, but it is not logis-
tically feasible. It would also result in an unacceptably high number of individuals
with a false-positive diagnosis of glaucoma.
Comment: To be effective,
screening programs should select participants at substantial risk for glaucoma.
- The cost-effectiveness of screening for POAG alone has not been demonstrat-
Comment: Cost-effectiveness for glaucoma may be enhanced when
done with other ocular conditions that cause visual impairment, including uncorrected
refractive error, cataract, diabetic retinopathy, and age-related macular degen-
- First-degree relatives of individuals with POAG and those with significant
risk factors should be examined.
Through the courtesy of the WGA and
Kugler Publications, you may now
download the PDF files of
Robert N. Weinreb, MD
Consensus Initiative Chair
World Glaucoma Association