Normal Tension Glaucoma:
Who Needs Neuroimaging?
Julie Falardeau, MD, FRCSC
Casey Eye Institute
Devers Eye Institute
Portland, Oregon
Background
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Normal tension glaucoma (NTG) is
characterized by:
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Cupping of the optic nerve head
Visual field loss
Intraocular pressure (IOP)  21 mmHg
No obvious or apparent cause for these
changes
Nonglaucomatous optic
disc cupping

Following an ischemic optic neuropathy
(anterior or posterior - AION or PION)
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Temporal arteritis
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Quigley and Anderson found that 50% of patient with
arteritic -AION developed cupping, compared to 10%
after non-arteritic-AION
Severe hypotensive/hypovolemic event
Demyelinating optic neuritis
Quigley et Anderson. Cupping of the optic disc in ischemic optic
neuropathy. Trans Am Acad Ophthalmol Otol. 1977;83:755-762
Nonglaucomatous optic
disc cupping
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Hereditary optic neuropathy
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Leber’s hereditary optic neuropathy
Autosomal dominant optic atrophy
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Traumatic optic neuropathy
Infectious
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Temporal disc excavation and pallor
Syphilis
Toxic
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Methanol
Nonglaucomatous optic
disc cupping
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Compressive lesion
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Meningioma
Aneurysm
Dolichoectasia of the internal carotid
artery
Suprasellar mass
Glaucomatous VS
Nonglaucomatous cupping

Distinguishing glaucomatous from nonglaucomatous disc cupping is often
difficult
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A detailed history is crucial
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Presence of neurological symptoms
Chronicity and pattern of visual loss
History of head trauma
History of shock or severe low blood pressure
Glaucomatous VS
Nonglaucomatous cupping
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Systematic approach recommended
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Demographic characteristics
Visual acuity
Optic disc characteristics
Visual field findings
Demographic characteristics

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A family history of glaucoma among
first degree relatives is highly
specific (96%) for glaucomatous
cupping
Age under 50 years is 93% specific
for nonglaucomatous cupping
Greenfield et al. The cupped disc: Who needs neuroimaging?
Ophthalmology. 1998;105:1866-1874
Visual Acuity

Patients with nonglaucomatous cupping
have significantly lower levels of visual
acuity than patients with glaucoma
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Trobe et al found all 20 patients with compressive
optic neuropathy had loss of central vision
Greenfield et al found visual acuity < 20/40 to be
77% specific for nonglaucomatous cupping
Hupp et al described sparing of central acuity in 3
of 6 eyes with compressive lesions
Optic disc characteristics
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Glaucomatous cupping:
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Vertical elongation
Cupping more than pallor
Greater frequency of peripapillary atrophy
Disc hemorrhage
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Highly specific
Nonglaucomatous cupping:
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Pallor of the neuroretinal rim
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Highly specific sign but relatively insensitive
The absence of disc pallor does not exclude
compressive lesions
Optic nerve appearance
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Baring of the circumlinear vessels
and temporal saucerization
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Common in glaucoma
Can also be seen in compressive optic
neuropathy
Kupersmith and Krohn. Cupping of the optic disc with compressive
lesions of the anterior visual pathway. Ann Ophthalmol 1984;16:948-53
Visual field findings
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Glaucoma
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Nerve-fiber-layer (arcuate) defects, bordering
horizontal midline
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Arcuate scotoma
Nasal step
Compressive lesion
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Central scotoma
Temporal hemianopia
Incongruous hemianopia respecting the vertical
meridian
Glaucomatous types of VF defects can occur
Humphrey perimetry in patients
with suprasellar mass
Ahmed et al. Neuroradiologic screening in normal-pressure glaucoma:
study results and literature review. J Glaucoma. 2002 Aug;11(4):279-86
NTG and Neuroimaging
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Some physicians routinely obtain
neuroimaging studies in patients
with NTG
Cost-to-benefit ratio of performing
such studies is unknown
NTG and Neuroimaging
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Ahmed et al found that routine
neuroimaging of NTG patients was
cost-effective
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6.5% of 62 consecutive patients with NTG had
clinically significant intracranial lesions
associated with optic neuropathy and visual
field loss typical of glaucoma
Ahmed et al. Neuroradiologic screening in normal-pressure glaucoma:
study results and literature review. J Glaucoma. 2002 Aug;11(4):279-86
NTG and Neuroimaging
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Steward and Reid reported
compressive lesions in 2 of 53
patients (3.8%) referred for
evaluation of NTG
In the series by Greenfield et al, none
of the patients diagnosed with
glaucoma had neuroradiological
evidence of compressive lesion
NTG and Neuroimaging
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In Bianchi-Marzoli at al’s series of 29
patients with cupping from unilateral
compressive lesion, only one had cupping
and field loss as an isolated manifestation
of their optic neuropathy
All others had:
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Reduced acuity
Decreased color vision
RAPD
Bianchi-Marzoli et al. Quantitative analysis of optic disc cupping in compressive optic
neuropathy. Ophthalmology 1995;102:436-440.
NTG: Who needs neuroimaging?
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Presence of headache or other
neurological symptoms
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Symptoms of decreased vision,
fluctuating vision, or visual field loss
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Atypical visual field for glaucoma
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Visual field defect respecting the vertical meridian
Junctional scotoma
Central or cecocentral scotoma
NTG: Who needs neuroimaging?
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Atypical rate of progression of VF
loss
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Monocular or binocular
Pallor > cupping
Asymmetric cupping
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Especially if progressive changes while
IOP remains symmetric and well
controlled
NTG: Who needs neuroimaging?
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Most likely NTG if:
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Vertical elongation of the cupping
Presence of notch
Presence of splinter hemorrhage
Family history of glaucoma