Normal Tension Glaucoma: Who Needs Neuroimaging? Julie Falardeau, MD, FRCSC Casey Eye Institute Devers Eye Institute Portland, Oregon

Background Normal tension glaucoma (NTG) is characterized by: 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) Temporal arteritis 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:

Nonglaucomatous optic disc cupping Hereditary optic neuropathy Leber’s hereditary optic neuropathy Autosomal dominant optic atrophy Temporal disc excavation and pallor Traumatic optic neuropathy Infectious Syphilis Toxic Methanol

Nonglaucomatous optic disc cupping Compressive lesion Meningioma Aneurysm Dolichoectasia of the internal carotid artery Suprasellar mass

Glaucomatous VS Nonglaucomatous cupping Distinguishing glaucomatous from non- glaucomatous disc cupping is often difficult A detailed history is crucial 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 Systematic approach recommended Demographic characteristics Visual acuity Optic disc characteristics Visual field findings

Demographic characteristics 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:

Visual Acuity Patients with nonglaucomatous cupping have significantly lower levels of visual acuity than patients with glaucoma 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 Glaucomatous cupping: Vertical elongation Cupping more than pallor Greater frequency of peripapillary atrophy Disc hemorrhage Highly specific Nonglaucomatous cupping: Pallor of the neuroretinal rim Highly specific sign but relatively insensitive The absence of disc pallor does not exclude compressive lesions

Optic nerve appearance Baring of the circumlinear vessels and temporal saucerization 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 Glaucoma Nerve-fiber-layer (arcuate) defects, bordering horizontal midline Arcuate scotoma Nasal step Compressive lesion 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 Aug;11(4):279-86

NTG and Neuroimaging Some physicians routinely obtain neuroimaging studies in patients with NTG Cost-to-benefit ratio of performing such studies is unknown

NTG and Neuroimaging Ahmed et al found that routine neuroimaging of NTG patients was cost-effective 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 Aug;11(4):279-86

NTG and Neuroimaging 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 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: Reduced acuity Decreased color vision RAPD Bianchi-Marzoli et al. Quantitative analysis of optic disc cupping in compressive optic neuropathy. Ophthalmology 1995;102:

NTG: Who needs neuroimaging? Presence of headache or other neurological symptoms Symptoms of decreased vision, fluctuating vision, or visual field loss Atypical visual field for glaucoma Visual field defect respecting the vertical meridian Junctional scotoma Central or cecocentral scotoma

NTG: Who needs neuroimaging? Atypical rate of progression of VF loss Monocular or binocular Pallor > cupping Asymmetric cupping Especially if progressive changes while IOP remains symmetric and well controlled

NTG: Who needs neuroimaging? Most likely NTG if: Vertical elongation of the cupping Presence of notch Presence of splinter hemorrhage Family history of glaucoma