Patients can present with a myriad of ocular complaints. Key questions include:

• History of previous ophthalmologic problems

• Temporal onset of vision loss

• Is there vision loss? If so,

  • Monocular or binocular vision loss

  • Pattern (scotoma, field, etc)

• Does the patient have double vision? If so,

  • Are the images duplicated in a horizontal, vertical, or skew pattern?

  • Any exacerbating factors?

    • Is the double vision worse when looking at a near or far object?

    • Does turning the head make the double vision worse?

  • Does the double vision resolve with covering one eye?

• Is pain associated with the vision loss?

  • Retro-orbital?

  • Pain with eye movements?

  • Other painful symptoms?

• When should ophthalmology be consulted urgently?

  • Monocular double vision

  • Inability to perform a good funduscopic examination without a dilated examination, and an ophthalmologic or vascular central retinal artery occlusion (CRAO) or central retinal vein occlusion (CRVO) cause is suspected

  • Suspicion of temporal arteritis

  • Monocular vision loss with a normal funduscopic examination by a neurologist when a primary neurological disorder such as migraines or multiple sclerosis (MS) is not suspected.

Visual acuity

Visual acuity should be measured on each patient. Different types of charts exist, and use is dependent on provider preference. Chart types include the following:

• Snellen eye chart is used at 20 feet or 6 feet distance, depending on the size of the chart.

• Rosenbaum vision chart is used at a distance of 14–16 inches.

• For patients who do not speak English, a tumbling E chart may be helpful. The patient identifies the direction of the E, that is, upward, downward, left, or right.

Using a pinhole can help to determine if vision correction can be helpful to improve the acuity, especially if the patient’s glasses are not available. Commercial pinholes are available or one can be made with a piece of paper. Simply create a hole with a needle or safety pin that is just large enough to see the images.

Eye movement and pupillary examination

• H test: patients with visual complaints or double vision should have extraocular movements tested in all directions.

• Pupil examination: light response with direct and indirect testing

• Indirect testing: swinging flashlight:

• Alternating shining a light between the eyes can be helpful in determining if an afferent pupillary defect (APD) is present.

• In an APD, the normal eye constricts, but when the flashlight is shined in the abnormal eye, the pupil dilates.

Optokinetics

• Use of an optokinetic flag or drum can be helpful in some cases. The patient is asked to hold their eyes in one location, while the flag is quickly moved in one direction. Optokinetic nystagmus (OKN) is present if the patient has an intact visual system.

• This test can be helpful in cases of suspected functional visual loss or in difficult-to-examine patients, although not all patients have a response. Volitional suppression by poor fixation is also possible.

Limits of direct ophthalmologic examination: If more than the disk needs to be seen, an ophthalmology consult should be considered. Small details, such as a branch retinal artery occlusion (BRAO), can be missed without a dilated eye examination. Patients with cataracts and other disorders may be difficult to visualize the disk.

Maddox rod²

• The Maddox rod can be helpful in identifying the abnormality in patients with double vision. The red glass is placed over the right eye, and a light is shined toward the patient. The patient maneuvers the rod to create a vertical line first. Both eyes remain open.

  • If the light is seen to the left of the vertical line, and the light and line become more divergent when looking to the right, then the patient has a lateral rectus palsy or sixth nerve palsy, that is, an esotropia.

  • If the light is seen to the right of the vertical line, and the light and line become more divergent when looking to the left, then the patient has a medial rectus palsy or another cause of an exotropia.

• The line can be placed horizontally to determine the hypertropic eye.

  • If the light is seen above the horizontal eye, then the left eye is hypertropic.

  • If the light is seen below the horizontal line, then the right eye is hypertropic.

Cover/uncover¹

• Covering individual eyes at near (33 cm) and far (6 m) can be helpful in determining the abnormal eye and requires no additional treatment.

  • If the left eye is covered, and the right eye adducts upon covering, then the patient has a right exotropia. Alternatively, if it abducts, then it is an esotropia.

  • If the left eye is covered, and the right eye moves downward, then the right eye is hypertropic. Alternatively, if it moves upward, then the right eye has a hypotropia.

Confrontational visual field (VF) testing—see Figure 25-1.

Acute bitemporal hemianopia

A patient with pituitary apoplexy needs urgent evaluation. Pituitary apoplexy occurs when hemorrhage or infarction of the pituitary gland occurs. Most often, this is within a pituitary adenoma.

Inciting events or other comorbid conditions can lead to pituitary apoplexy

These include:

• Hypertension

• Angiography

• Major surgeries

• Increased intracranial pressure (ICP)

• Head trauma

• Medication use:

  • Anticoagulants

  • Dopamine agonists

• Radiation

• Pregnancy

• High-dose estrogens

Inciting events or other comorbid conditions can lead to pituitary apoplexy.

Signs and symptoms of pituitary apoplexy:

• Headache in 80%

• Cranial nerve (CN) abnormalities, specifically oculomotor (CNIII), trochlear (CNIV), or abducens (CNVI)

• Photophobia

• Meningismus

• Nausea

• Vomiting

• Altered consciousness

• Fever

• Focal neurological deficits due to compression of the intracranial carotid artery

Endocrine signs and symptoms may also be present

• Blood pressure abnormalities and hyponatremia can occur with corticosteroid deficiency.

• Diabetes insipidus

MRI or CT scan can be very helpful

• CT can help to rule out subarachnoid hemorrhage (SAH) and will show an intrasellar mass. Most of the time, hemorrhage of the pituitary adenoma can be seen.

  • Contrast can be given and the pituitary appears hyperdense and heterogenous. Ring enhancement or a fluid level can be seen.

• MRI can show blood in the subacute setting, but can also show the mass effect on surrounding structures.

Treatment

• Hydrocortisone

• Surgical consultation for transphenoidal approach

Acute homonymous hemianopia

Visual field localization can be easily performed in this case. There are two possible localizations: the left optic tract or the left occipital lobe. Macular sparing helps to identify the occipital lobe as the localization.

Tunnel vision and other functional visual loss

What additional tests can be done to confirm your suspicions?⁴

Several bedside tests can be done to evaluate a patient with functional vision loss.

Tunnel vision and other functional visual loss

• Tunnel vision is not physiologic. Testing the visual fields at various distances should create a funnel-like shape in patients with true central-only vision. A tube-like shape is suggestive of a nonorganic pattern.

• Use the finger-nose-finger examination to test peripheral fields. The patient should be unable to accurately reach the finger if peripheral vision is truly lost.

For decreased visual acuity:

• Give the patient choices. Use a tumbling E chart to determine the direction of the E, but only give the patient two choices. If the patient chooses too many or too few correct responses, a functional neurological disorder should be considered.

• Encourage the patient to read the smallest line on visual acuity testing. Cover up the rest of the chart, so the patient does not know that they are being encouraged to read the smallest line. Continually show larger and larger lines. Often, the patient with a functional neurological disorder is able to read the 20/20 or 20/30 line.

• Double the distance of the vision chart from the patient. If they can read the same line in both positions, then the vision impairment is most likely functional.

For severe or total vision loss:

• Blinking to threat should be impaired in patients with organic disease.

• An APD is present if monocular vision loss is present.

• An optokinetic flag or drum can be used. If the patient has better than 20/400 vision, then OKN may be present.

For physiologic monocular double vision, the double vision should resolve with pinhole testing.

What are some normal variants that can be confused with abnormal pupillary function?

• Hippus

  • Constriction of pupil followed by dilation and constriction again. The pupil size varies by less than a millimeter.⁵

  • Occurs in normal individuals after light is shined in the eye.

• Anisocoria

  • Unequal pupils, usually less than 1 mm

  • Common, and can occur in 20% of people.⁶

  • Normal response to light, accommodation, extraocular movements, and lids.

• Post-surgical pupils

  • Often, postsurgery, pupils can be shaped irregularly or not constrict to light as well as a pupil that has not had surgery.

What is the most likely cause of unequal pupils in this case?

Pharmacological alteration of the pupils is common in the inpatient setting. Anticholinergic agents such as ipratropium, scopolamine, and atropine are common offenders. Medication can enter the eye when the patient’s hand comes in contact with the medication and the eye is rubbed. Alternatively, nebulizers that are given can be aerosolized into the eye with a poorly fitting mask. The normal examination rules out intracranial hypertension and herniation. The effects of the medication should resolve with time, while more insidious causes would be persistent.⁷

How do you approach anisocoria in this patient?

Evaluating the pupils and eyelids in bright light and the dark is helpful.

• If the anisocoria is greater in the dark than in the light, then the abnormal pupil is the smaller one.

  • Consider a third nerve palsy or a midbrain lesion if there are extraocular movement abnormalities or ptosis.

    • Pilocarpine makes the pupil smaller in a third nerve palsy.

    • If only the pupil is involved, consider a posterior communication aneurysm, increased ICP, or stroke as possible causes.

  • Tonic pupil

    • Poor response to light helps differentiate from other causes.

    • Acute phase: dilated and poorly reactive pupil. Patients have photophobia and blurry vision with accommodation.

    • After a few weeks: pilocarpine challenge. The larger, abnormal, pupil constricts more than the smaller, normal, one.⁸

    • Chronic: If you ask the patient to transition from a near object to a far object, the contralateral pupil dilates and the abnormal pupil appears smaller than the normal pupil.

• If the anisocoria is greatest in the light, then the abnormal pupil is the larger one.

  • Horner syndrome is a common cause. Ptosis, miosis, and anhydrosis are classic findings, although all three are not always seen. Anhydrosis is only seen with preganglionic disorders.

    • Hydroxyamphetamine administration can cause dilation of the abnormal pupil in a preganglionic Horner syndrome but not in a postganglionic Horner syndrome, such as in cases of internal carotid artery (ICA) dissection.

    • Cocaine has no effect on the size of the smaller pupil, but dilates the larger pupil.

    • Hydroxyamphetamine and cocaine should not be used within 24 hours of each other.

    • Apraclonidine administration causes dilation of the smaller pupil and constriction (or no change) of the larger pupil. Confirms that a Horner syndrome is present.

How does the onset of the symptoms help narrow the diagnosis?

• Because the finding is new, the patient most likely does NOT have

  • Holmes-Adie pupil

    • Possibly due to a viral infection

    • More common in young women

    • Dilated pupil with photophobia and blurry vision

  • Syphilis

    • Can cause an Argyll Robertson pupil

      • Light-near dissociation: accommodates but does not react.

      • Diabetes can cause a similar picture.

  • Iris disease

    • Iritis can cause a small pupil. The pupil can be irregular and not react to light. The patient may have a red eye and complain of light sensitivity.

Is this something you need to be concerned about?

Usually not. Mydriasis can occur in women with migraines and can occur with or without a headache. The anisocoria usually resolves within a few hours.⁸

You are concerned about missing glaucoma. What are characteristic signs and symptoms?

Intermittent subacute angle-closure glaucoma needs to be addressed immediately with an ophthalmology examination. Patients can have eye pain and redness. They complain of blurry vision as well as seeing halos when looking at a light. Headaches, sometimes severe, can occur. See above for additional information on glaucoma.

What are the differential diagnosis?

Botulism and Fisher variant of Guillain-Barré Syndrome (GBS) are both on the differential for this patient. More history regarding clinical symptoms would be ideal. Fisher variant of GBS is at the top of the differential list, especially since the patient had an illness a few weeks in the past (see Chapter 42).

Miller-Fisher syndrome

• Classic symptoms include ophthalmoplegia, ataxia, and areflexia.

• In about half of these patients, early in the disease course mydriasis with poor or no pupillary response can be seen.

• Light-near dissociation may also be seen.

Botulism

• Most have blurry vision with reading at the onset.

• The blurry vision is out of proportion to the pupillary abnormalities, which is an impaired pupillary light response.

• Descending muscle weakness, impaired extraocular movements, autonomic dysfunction, and bulbar paralysis can occur.

Most patients in coma have their eyes closed. Physical examination findings may be dependent on the cause of coma.

• Conditions that damage or cause dysfunction of both cerebral hemispheres may have normal pupillary response. Brainstem function may be normal, including oculocephalic responses.

• Cerebral hemisphere/cerebellar mass effect on the brainstem can cause cranial nerve abnormalities, including third nerve palsies.

• Brain stem abnormalities can cause cranial nerve deficits, including unilateral abnormal oculocephalic responses.

• Toxic metabolic dysfunction can cause a variety of ocular responses, ranging from normal responses, roving eye movements, and absent responses.

• Lesions above the thalamus and below the pons have normal pupillary responses.

The eyes can be deviated or disconjugate, especially if there is a lesion present in the paramedian pontine reticular formation (PPRF), frontal eye fields (FEF), the brainstem, or mass effect. It is difficult to localize upward or downward deviation of the eyes. In cases of subclinical status epilepticus, the eyes may be deviated or have small jerking movements.

Spontaneous eye movements can occur

• If purposeful movements are present, think of conditions other than coma. Locked-in syndrome, catatonia, and psychogenic coma may be potential causes.

• Roving eye movements are common in toxic/metabolic causes of coma and of bilateral cerebral hemispheric dysfunction (Figure 25-2).

Correct diagnosis depends on accurate localization, which depends on accurate history and examination

The first step is determining whether the diplopia is monocular or binocular and therefore whether the issue is likely an ophthalmologic or neurologic problem, respectively (Figure 25-3). Monocular diplopia is most often due to ocular pathology such as cataracts or severe refractive errors. In contrast, binocular diplopia is due to an abnormality of ocular alignment, often of neurologic origin and the subject of this part of the chapter. Rare exceptions to this efficient method of localization and triage include polyopia, due to lesions in the parietal occipital regions. In contrast, there is some macular pathology that can cause binocular diplopia, which is in fact ophthalmologic, including epiretinal membranes.¹¹

• Orientation: horizontal, vertical, oblique (both vertical and horizontal vectors)

• Is it worse with a certain direction of gaze?

• Worse with focus on near or far targets?

• Temporal profile—stable versus fluctuating or history of fatigability

• History of recent trauma

• Review of systems: headache—more common in nonischemic causes of ophthalmoplegia (aneurysm, meningitis, trauma), fever, stiff neck

Examination techniques—there is a more comprehensive discussion of examination techniques for visual complaints in Part 1.

Basic anatomy

• Nucleus and origin in the dorsal midbrain adjacent to the periaqueductal gray matter

• Ipsilateral and ventral exit

• Superior (levator palpebrae, superior rectus) and inferior branches (inferior rectus, medial rectus, inferior oblique, iris sphincter, ciliary muscles)

• Topographic organization of the nerve

  • Pupillomotor fibers—located dorsally and peripherally

  • Oculomotor fibers—located centrally

Functions

• Adducts, elevates, and depresses the eye

• Lid elevation

What other examinations should be considered given we suspect a third nerve palsy and why?

• Need to establish if this is an isolated third nerve palsy or if this is nonisolated by searching for other signs.

• Examination of the orbits for signs of

  • Chemosis

  • Proptosis

  • Lid swelling

• Examine other cranial nerves to rule out multiple cranial neuropathy

• Examine for other brainstem findings that might indicate a nuclear or fascicular lesion.

Causes

• Aneurysm (posterior communicating artery [PCOM], posterior cerebral artery [PCA])—most urgent consideration

• Ischemic palsy/microvascular—most common cause

  • Diabetes mellitus—most common association

  • Giant cell arteritis (GCA)

  • Systemic lupus erythematosus (SLE)

• Traumatic

• Tumor

• Infection—meningitis

• Cavernous sinus syndrome

• Orbital syndrome

Fascicle

• Rarely occurs in isolation

• Can spare the pupil

• Has been described as affecting individual muscles¹²

• Has been associated with several lesional midbrain syndromes:

  • Nothnagel—with ipsilateral ataxia from involvement of the superior cerebellar peduncle

  • Claude—with contralateral ataxia from involvement of the superior cerebellar peduncle

  • Benedikt—with contralateral tremor from lesions in the red nucleus

  • Weber—contralateral hemiparesis from lesions in the ipsilateral cerebral peduncle

Evaluation

What test(s) should be done immediately (Figure 25-4)?