E. Lee Murray, MD
CHAPTER CONTENTS
◦Partial-Field Versus Full-Field
◦Localization of Lesions Producing Diplopia
•Papilledema and Optic Disc Edema
OVERVIEW
The most common visual complaints seen by the hospital neurologist are:
This chapter discusses the presentations of some common visual complaints, localization of the lesions, and possible diagnoses. Specific diagnoses are discussed in their respective chapters. For interested readers, Lemos and Eggenberger recently published an excellent review which is available for free download from PMC.1
VISUAL LOSS
Visual loss is organized into diagnoses depending on whether the loss is monocular or binocular, partial field or full-field. Of the partial field defects, a further distinction is made depending on the geometry of the visual loss.
Monocular Versus Binocular
Monocular visual loss suggests a lesion affecting the eye or optic nerve. Important causes are optic neuritis (ON), ischemic optic neuropathy, or intraocular pathology (e.g., hemorrhage).
Binocular visual loss indicates a lesion at or behind the optic chiasm or lesions of both optic nerves. If the visual loss is congruent, then a lesion behind the chiasm is indicated. If the lesion is incongruent (e.g., bitemporal hemianopia), a lesion in the region of the chiasm is suggested. Note that patients might report visual deficit in one eye when they actually mean to one hemifield—for example, a right homonymous hemianopia can present with a patient complaining of visual loss in the “right eye.”
Partial-Field Versus Full-Field
Full-field monocular visual loss suggests catastrophic damage affecting the eye or optic nerve. The spectrum of potential diagnoses is broad, but includes ON, ischemic optic neuropathy, and intraocular hemorrhage.
Full-field binocular visual loss suggests either bilateral occipital ischemia or bilateral ON; speed and mode of onset of the deficit help to distinguish between these two possibilities. Psychogenic visual loss can also present as total visual loss.
Partial-field visual loss also has a broad differential diagnosis partly depending on the geometry of the visual loss:
•Homonymous hemianopia indicates a lesion of the contralateral optic radiations or occipital cortex.
•Bitemporal hemianopia indicates a lesion of the optic chiasm.
•Binasal hemianopia also suggests a lesion in the region of the chiasm, but of a geometry that compresses uncrossed axons laterally in the chiasm. Binasal hemianopia is rare but has been reported to be due to a wide variety of causes and may even be idiopathic or possibly congenital.2
Timing of the Visual Loss
Timing of the visual loss narrows the differential diagnosis. Acute visual loss is usually vascular, although ON and acute glaucoma can seem acute. Note that visual difficulty is usually noticed acutely, often with a sense of alarm, so an insidious visual loss may be reported as acute because a threshold for symptomatology was reached.
Localization and Diagnosis
Localization and a brief differential diagnosis for specific types of visual loss are presented in Table 6.1. Specific entities are discussed in their respective chapters.
Table 6.1 Localization and diagnosis of visual field defects
Syndromes of Visual Loss
Syndromes of visual loss presenting to the neurologist are described here. Specific entities are discussed in more detail in their respective chapters.
•Transient monocular blindness: Acute visual loss in one eye, lasting 5–10 minutes then resolving. Exam is typically normal by the time of presentation.
•Ischemic optic neuropathy: Acute visual loss in one eye, which may improve but does not resolve. Exam shows visual loss and often signs of retinal vascular changes.
•Optic neuritis: Subacute onset of blurry vision or visual loss over hours to a day. Often with eye pain. May be unilateral or bilateral; exam often shows papilledema, but not invariably.
•Glaucoma: Unilateral or bilateral visual loss, often painful with acute exacerbation of glaucoma. Exam may be normal except for tonometry showing increased ocular pressure.
•Pseudotumor cerebri: Usually bilateral subacute visual loss is present, often with headache. Exam shows papilledema.
•Stroke: Acute onset of visual loss that can be hemianopia, quadrantanopia, or incongruous. Usually associated with signs of other neurologic deficits.
•Temporal arteritis: Temporal pain in middle to late age that can lead to blindness from ischemic optic neuropathy. Suspected by temporal artery thickening and/or tenderness.
•Intraocular hemorrhage: Acute or subacute onset of monocular visual loss. Ocular exam shows characteristic appearance, whether subretinal, vitreous, or anterior chamber hemorrhage. May produce ocular pain.
•Retinal detachment: Acute or subacute onset of visual obscuration as a shadow or curtain over vision. May produce ocular discomfort.
EYE PAIN
Many causes of eye pain do not present with visual loss or other neurologic symptoms and are not considered here, including conjunctivitis, keratitis, or blepharitis. Isolated eye pain usually does not present to the neurologist, but visual disturbance with eye pain may include a number of structural and inflammatory disorders. Differential diagnoses of eye pain include:
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