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  INTRODUTION

  
  
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  CHIEF COMPLAINT AND HISTORY OF PRESENT ILLNESS

  
  
  
  
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    Visual loss

    
    
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    Positive visual and hallucinations

    
    
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    Diplopia

    
    
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    Ptosis Anisocoria

    
    
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    Pain and Photophobia

  
  
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  REVIEW OF SYSTEMS AND OTHER HISTORY

  
  
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  EXAMINATION OVERVIEW

  
  
  
  
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    Function

    
    
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    Structure

    
    
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    Putting it all together

  
  
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  EXAMINING THE EYE AND ORBIT

  
  
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  CLINICAL ANCILLARY TESTS

  
  
  
  
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    Photography

    
    
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    Intravenous fluorescein angiography

    
    
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    Optical coherence tomography

    
    
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    Ultrasonography

  
  
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  NEUROIMAGING

  
  
  
  
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    Computed tomography

    
    
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    Magnetic resonance imaging

    
    
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    Imaging the orbit

    
    
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    Imaging the brain

    
    
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    Cerebral angiography

    
    
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    Functional neuroimaging

  
  
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  KEY POINTS

The art and science of obtaining a meaningful history is the keystone of neuroophthalmology. Some may doubt the importance of the history in ophthalmology—because the examiner has the unique ability to actually see the organ of interest inside and out in vivo (unlike the cardiologist or nephrologist)—but a single day in a busy neuroophthalmology clinic will put that notion to rest.

We do not wish to imply that neuro-ophthalmic history-taking should be a lengthy, memorized barrage of questions relating to every system in the body. Instead, the effective examiner is similar to a mechanic with a large chest of tools, carefully selecting the correct instruments for the task at hand. Because effective history-taking depends on a thorough knowledge of the many manifestations of disease in the visual system, it is truly the most complex “procedure” a physician can perform on a patient. A guide, outlining the components of the neuro-ophthalmic history, is provided in Table 1–1.

Neuro-ophthalmic chief complaints usually concern visual loss, positive visual phenomena, diplopia, ptosis, anisocoria, pain, and photophobia. Vision complaints are often difficult for patients to articulate. In addition, neuro-ophthalmic patients commonly present with an array of seemingly disjointed complaints, offering a considerable challenge to even to the most determined historian. For this reason, crystallizing the patient’s concerns into a list of individual complaints, prioritized by the patient’s degree of concern, is vital. Information concerning each complaint can then be gathered logically. At the end of the history and examination, the physician can then return to this list to form an assessment and devise a plan that specifically addresses the patient’s reason for seeing the physician. Even if the examination reveals more serious concerns, the patient’s original complaints should not be ignored. Even if you have made a life-saving discovery in your history and examination, the patient is unlikely to be satisfied until you have also addressed the patient’s initial concerns.

The history of present illness is an expanded description of each complaint, exploring characteristics such as those listed in Table 1–2. In this era of the electronic medical record (EMR), the patient’s history is expected to fit into convenient “one-size-fits-all” drop-down menus. Even if EMR limits how the history is officially recorded, physicians should not be limited in how they collect and think about the patient’s history. Complex histories are often best assessed by plotting the patient’s progression of symptoms, treatments, and associated factors over time. This process is especially helpful when the patient can see a plot in progress (eg, sketched on paper or on a dry-erase board in the examination room) as the history is being collected (Figure 1–1).

In the first half of this chapter, important elements in the history of present illness (see Table 1–2) are used to illustrate common neuro-ophthalmic histories. The examples given are not all-inclusive, and will make more sense when specific disorders are covered in detail in later chapters. The intent here is to convince the reader that the details of the patient’s history are important, and that they are often crucial to determining the diagnosis.

VISUAL LOSS

The sensory experience that we call vision is not easily described. “Vision” includes the complexities of shape, color, contrast, stereopsis, and movement across the vast visual fields of both eyes. Not surprisingly, patients may have difficulty finding precise words to describe abnormalities in the quality of their visual experience.

Visual loss may be described by patients as blindness, blurriness, or dimness; a skim, cloud, curtain, or screen covering vision; washed-out color; or broken, twisted vision (metamorphopsia). The descriptions patients choose are helpful. For example, patients with optic neuropathies often describe their vision as dim or dark, whereas patients with cataract are more likely to report blurriness. Complaints of poor color vision are common with optic neuritis. Metamorphopsia is almost always the result of macular disease.

Patients may be able to localize their visual disturbance to one eye, or to a portion of the visual field. Patients typically have difficulty understanding homonymous (see Box 3–1) visual field loss, ascribing the problem exclusively to the eye on the side of the visual field loss. Visual loss may be global, affecting the entire visual field of one or both eyes, or may be confined to a specific area of the visual field. Patients with anterior ischemic optic neuropathy frequently describe loss of the lower or upper half of their visual field. Patients with central visual field loss may report that objects seem to disappear into a central cloud when they try to look at them, but are made clearer when they look to the side. Formal perimetry provides a more quantitative assessment of a visual field defect, but much can be learned by listening to the patient’s qualitative description.

The severity of visual loss can be assessed by what a patients could or could not do with their degree of visual loss. For example, a patient with a scintillating scotoma from migraine may continue to work at the computer during an episode; a patient with progressing cataract may have given up playing cards or driving.

The time course of visual loss is often the most important diagnostic clue in the history (Figure 1–2). Visual loss may be unchanging, improving, worsening, fluctuating, or transient. The time course in transient visual loss is particularly important, because no signs or symptoms may be apparent at the time of the examination (Table 1–3).

In some cases, it may be difficult to ascertain if monocular visual loss truly occurred suddenly, or if it is a problem of long duration that was discovered suddenly when the normal-seeing eye was incidentally covered. For example, a patient may discover poor vision in his right eye when using a rifle site at the start of hunting season.

The context of visual loss—the surrounding circumstances of the event—provides many diagnostic clues that are usually self-evident, such as traumatic optic neuropathy in the setting of a blow to the brow, or retinal emboli after carotid endarterectomy or cardiac surgery.

Patients should be asked about what may modify the symptoms—circumstances that make their vision better or worse. In transient visual loss, particular precipitating factors should be sought. Increased body temperature from a hot shower or sauna may cause blurring of vision in patients who have had optic neuritis (Uhthoff phenomenon). Transient visual obscurations frequently occur with postural changes in patients with papilledema.

Associated symptoms may also provide major diagnostic clues, such as scalp tenderness and jaw claudication with visual loss from giant cell arteritis, or pain with eye movement associated with optic neuritis.

POSITIVE VISUAL PHENOMENA AND HALLUCINATIONS

Aberrations of vision may be negative or positive. Visual loss—defects or deficiencies in the sensory visual experience—is a negative visual symptom. Positive visual symptoms involve seeing things that are not images of the real world, described by patients as flashes, lightning streaks, jagged lines, complex patterns of color and form, or formed hallucinations and illusions (Box 1–1). Patients are often reluctant to tell their physician if they are “seeing things,” and may need to be specifically asked. The source of positive visual phenomena may be the eye itself (entoptic phenomena such as flashes from retinal traction or detachment), “release phenomena” generated by the central nervous system (CNS) in blind areas of the visual field, or true hallucinations from CNS disease (Table 1–4).

Localization may be helpful: bright, brief flashes from a vitreous or retinal detachment are typically seen in the temporal visual field; migraine aura are homonymous. The formed hallucinations of Charles Bonnet syndrome (Box 1–2) are visualized in the nonseeing portion of the visual field: central in macular degeneration, in a homonymous pattern in occipital disease.

As with other symptomatology, the time course is often diagnostic. The scintillating scotoma of migraine starts small and expands over 15 to 45 minutes. Flashes from vitreous/retinal pathology are described as “like lightning.” Phosphenes, lasting seconds, can occur with optic neuritis, often in response to sudden loud noises.

The context, especially with formed hallucinations, is helpful: delirium in alcohol withdrawal, hallucinations in Parkinson disease, hypnagogic and hypnopomic hallucinations seen with narcolepsy and sleep apnea.

The association of headache following a migrainous scintillating scotoma is well known, but patients can have acephalgic (no headache) migrainous visual aura.

DIPLOPIA

Technically, diplopia refers to seeing the same image twice in a given field of view. However, the main reason patients are symptomatic with diplopia is that it is accompanied by confusion. In confusion, two superimposed images occupy the central vision, causing confusion as to which is the real “straight ahead” image. In general, patients (and physicians) find it easier to discuss diplopia/confusion in terms of “double vision” and the separation of two identical images. Diplopic images that are minimally separated may be described as blur rather than double: the unwary examiner may be convinced that “blur” must mean an afferent disorder (cataract, optic neuritis, etc) and miss an ocular motility disorder.

Diplopia resulting from binocular misalignment (strabismus) typically produces double images that are equally clear. In this case, the patient’s diplopia disappears when either eye is covered. Monocular diplopia is present even when a single eye is viewing alone, and is frequently caused by anterior segment disorders (Table 1–5). Patients with supranuclear palsies usually have vague visual complaints, and unlike other motility disturbances only occasionally describe double vision, despite an obvious misalignment of the eyes. Patients with congenital strabismus or long-standing ocular deviations often develop effective suppression of a misaligned eye and therefore may not experience diplopia.

The patient’s description of the relative orientation of the two images in diplopia, and how this orientation changes in different directions of gaze, has great diagnostic value. Sixth cranial nerve palsies result in horizontal diplopia, with greatest separation of the images in the direction of the palsied lateral rectus muscle. Diplopia may not be present at near or when gaze is directed away from the palsied muscle in this condition. Vertical or diagonal diplopia may be the result of third or fourth cranial nerve palsies. A “tilt” to one of the images is typically reported with fourth cranial nerve palsies. Ocular myasthenia may cause diplopia of any orientation that may change over time. Diplopic images that are greatly separated may be better tolerated, because the second image is more easily ignored than when the competing images are close together or overlapping.

Understanding the time course and duration of diplopia is important. Transient or variable diplopia may be the result of a transient ischemic attack, vertebrobasilar insufficiency, decompensating strabismus, or myasthenia gravis. Diplopia that is abrupt in onset suggests a vascular event such as an ischemic cranial mononeuropathy (cranial nerves [CNs] III, IV, or VI) or a brainstem ischemic event. Ischemic cranial mononeuropathies typically resolve completely in 8 to 12 weeks. Gradually worsening diplopia suggests compression of CNs III, IV, or VI, or an orbital process such as orbital Graves disease. Patients with ocular myasthenia may describe a lengthy history of intermittent, variable diplopia, often worsening toward the end of the day.

Examples of the importance of the context in which diplopia occurs include post-lumbar puncture sixth cranial nerve palsies, vertical diplopia after cataract surgery, or skew deviation after brainstem stroke. Head trauma is a common cause of fourth, sixth, and occasionally third cranial nerve palsies, and may also cause diplopia from extraocular muscle injury or entrapment in an orbital fracture.

Patients should be questioned about any factors that modify their symptoms. Diplopia from myasthenia gravis is typically improved on arising in the morning and after a nap, and worsened with fatigue. As previously discussed, binocular diplopia should vanish if either eye is covered. Patients who complain of diplopia but do not spontaneously close or cover one eye likely have monocular diplopia (from cataract or other ocular cause), rather than a neurological cause.

The presence of ptosis or anisocoria is of particular importance in assessing ocular motility disturbances. Third cranial nerve palsies are usually associated with a ptosis of the involved eye. The presence of a dilated pupil in this setting may suggest a compressive, rather than ischemic, mechanism. Myasthenia may cause ptosis of either one or both eyelids, and may be associated with ocular misalignment (but not anisocoria), facial weakness, or systemic (proximal limb and bulbar) weakness. Eyelid retraction (with “scleral show”) frequently accompanies the diplopia from orbital Graves disease. The character of the pain associated with diplopia may help differentiate possible diagnoses such as giant cell arteritis (vasculitic ischemic cranial mononeuropathy), ophthalmoplegic migraine, aneurysm (compression of the third cranial nerve), idiopathic orbital inflammatory syndrome, and other disorders.

PTOSIS (BLEPHAROPTOSIS)

Patients describe ptosis in a number of imaginative ways, including “swelling” of the eyeball or eyelid, “one eye smaller than the other,” or as a “lazy eye.”

Occasionally patients may complain of a droopy eyelid when the eyelid retraction of the contralateral eye is the real problem. Asymmetric bilateral ptosis may be attributed only to the worse eye by the patient. Ptosis from an oculosympathetic paresis usually only measures 1 to 2 mm, whereas ptosis from a third cranial nerve palsy can range from minimal to total. Blepharospasm is spontaneous activation of the orbicularis muscles (overacting eyelid protractors), and may occasionally be confused with ptosis—a deficiency of lid elevation (weak eyelid retractors). An apparent bilateral ptosis can occur from CNS disease causing an inability to open the eyes known as apraxia of eyelid opening.

Patients may not be aware how long ptosis has been present, especially a minimal ptosis that is functionally asymptomatic. Old photographs provide an objective record of the patient’s appearance. A drivers’ license or other photos in the patient’s wallet (or on his or her cell phone) are immediate sources, or the patient may need to bring other photographs from home on subsequent visits (Box 1–3). Variability of ptosis with fatigue and ptosis that “switches eyes” over time are hallmarks of ocular myasthenia.

The history may place ptosis in the context of trauma, contact lens wear, topical ocular medications, ocular surgeries, or neurosurgical procedures, narrowing the differential diagnosis.

A smaller pupil associated with a ptotic lid may represent an oculosympathetic paresis, whereas a larger pupil with ptosis suggests the possibility of a third cranial nerve palsy. Disorders that cause ocular pain may be the source of a “protective ptosis.”

ANISOCORIA

Patients may discover pupillary inequality themselves, especially when they have lightly colored irides. More frequently, it is someone else—a family member, friend, or physician—who notes a difference in pupil size between the two eyes, sending an otherwise asymptomatic patient for further evaluation. Thus, patients with anisocoria usually have fewer observations to volunteer than those with diplopia or visual loss.

Which pupil is the abnormal one is not always obvious. Although patients are quick to ascribe pupillary inequality to a “bad eye,” the examiner will need to wait for the pupillary examination to determine which pupil—the smaller or the larger of the two—is the abnormal one.

Although certain conditions cause intermittent pupillary dilation, the variability of anisocoria reported by the patient is most likely the result of changes in lighting conditions and accommodation. Interestingly, patients who examine their own pupils in the mirror will only observe the pupil size in an accommodative state, typically in a bright light—minimizing the anisocoria in Adie pupil and Horner syndrome. As with ptosis, examination of the patient’s driver’s license or other photographs (with magnification provided by the slitlamp or an indirect ophthalmoscopy lens) may establish the duration of anisocoria. The importance of the pupil size and its association with ptosis and diplopia has been discussed. Adie pupil is usually associated with transient blurred vision when accommodation is changed from near to distance, because of tonicity of accommodation.