Chapter 2: Visual Problems

Jade Schiffman MD, FAAN, FAAO; Rosa Tang MD, MPH, FAAO; Barbara Scherokman MD, FAAN, FACP; Myriam Jones MD, FACP

I. CASE HISTORIES

Case 2-1. A 72-year-old woman with a history of diabetes, high blood pressure, and proximal joint arthritic pain presents with a one-month history of right-sided headache. The pain is aching and constant. At times her right eye is painful.

1. What other historical points are important to ask this patient?
2. What etiologies for her eye pain would you consider?
3. What would be your first steps in evaluating and managing this patient?

Case 2-2. A 36-year-old woman developed episodes of transient flashes of light in her right eye lasting 10 minutes and occurring about once a week for the past two months. Occasionally she gets a dull global headache following the visual phenomena.

1. What historical feature is important to differentiate between ocular or neurologic cause?
2. If this is a binocular occurrence of flashing light, what is the most likely etiology that you would consider

II. DISORDERS

The two major systems that provide normal visual function are the ophthalmic and neurologic systems. Numerous disorders can affect vision, and when evaluating patients with visual complaints it is important to initially determine if their symptoms and signs fit into either ocular or neurologic dysfunction.

As with all neurologic disorders, the examination is used to localize the problem in the nervous system, and the time course is then used to narrow down the possible etiologies. Table 2-1 categorizes common or dangerous etiologies based on localization and time course.

Table 2-1 Disorders Causing Visual Problems: Localization/Time Course

The following discussion will first focus on a brief general bedside examination of visual complaints. The important historical questions, etiologies, red flags, and timing of workup and referral will then be discussed for the four major visual complaints: (1) blurred/loss of vision, (2) extraocular movement disorders/double vision, (3) eye pain, and (4) anisocoria/ptosis.

III. EXAMINATION

The visual system examination (Video 2-1) consists of three parts (close one eye, visual fields, and extraocular movements). Patients often do not know if their visual disturbance is in one eye only or both eyes. If the complaint is truly monocular, then an ophthalmic cause is much more likely. If the abnormality is in both eyes, then neurologic disorders are the usual cause. Therefore, it is extremely important to determine whether the complaint is in one or both eyes. The patient should be asked to close one eye and then the other to determine if the diplopia or blurry vision resolves. Remember that normal patients often experience diplopia when their glasses are removed only because of the refractive error.

In the case of a visual field defect, such as a homonomous field defect, patients frequently say that they cannot see out of one eye. For example, patients with a left homonomous hemianopia (Figure 2-1) commonly say they cannot see out of their left eye when in fact they are unable to see out of the right nasal and left temporal fields. Their initial complaint sounds monocular, but their true problem is binocular. The visual fields can be checked with one eye fixated on the examiner's nose and the other eye covered. The examiner then holds his or her hands up in front of the patient in the two upper fields (temporal and nasal) and asks the patient if he or she can see both hands equally. The exam is repeated with the hands in the inferior fields. Then the other eye is checked in the same manner.

Figure 2-1 Left Homonymous Hemianopia

Extraocular movements are checked by asking the patient to follow the examiner's finger starting in neutral (straight ahead) position. The eyes are observed for nystagmus (rapid involuntary rhythmic eye movements) and any ocular deviation causing a dysconjugate gaze. The finger is then moved horizontally to the right and left into far lateral gaze. It is important to look for nystagmus at far lateral gaze and for any misalignment of the eyes. It is also important to look for any asymmetry. The finger is then moved in the midline up and down to the far reaches of gaze, again looking for nystagmus or dysconjugate gaze.

IV. BLURRED/LOSS OF VISION

In addition to determining the suddenness of onset of symptoms, important historical points for evaluation of blurred or loss of vision fall under the categories in Table 2-2. This table also describes etiologies and how quickly the patient should be evaluated or referred. In general, the more rapid the onset of the visual difficulty, the more rapid the workup or referral should be. In most cases patients with acute truly monocular visual disturbance should be referred immediately to ophthalmology. Acute binocular difficulty requires an urgent neurology referral. One should always keep in mind giant cell arteritis (temporal arteritis) in patients over the age of 50. These patients frequently have jaw claudication, polymyalgia rheumatica, temporal artery tenderness, and elevated sedimentation rate and C-reactive protein.

Table 2-2 Blurred/Loss of Vision: Historical Points, Etiology, and Evaluation/Referral

Several etiologies in Table 2-2 should be emphasized. Carotid dissection (Figure 2-2) is one of the dangerous causes of monocular transient visual disturbance. Patients also present with headache, neck pain, or eye pain.

Figure 2-2 Right Carotid Dissection

For binocular visual disturbances, migraine aura is extremely common. Migraine aura causes positive visual phenomena (flashing lights, zigzags, heat waves) that change over time (Figure 2-3) and usually lasts longer than 20 minutes.

Figure 2-3 Visual Aura Changing over Time

V. EXTRAOCULAR MOVEMENT DISORDERS/DOUBLE VISION

A variety of problems fall under the heading of eye movement disorders. Nystagmus is suggestive of a brainstem or vestibular disorder. Patients may complain of oscillopsia, which is a subjective sensation of movement of the environment. Patients with nystagmus should be referred to neurology. Double vision is divided into monocular, which is most likely ocular in etiology, and binocular, which tends to be a neurologic problem (Table 2-3). Patients may state that their double vision is in both eyes; however, when one eye is covered the abnormality is in fact monocular.

Table 2-3 Double Vision: Historical Points, Etiology, and Evaluation/Referral

VI. EYE PAIN

Patients with eye pain usually have an ocular disorder such as dry eye, iritis, keratitis, uveitis, acute glaucoma, episcleritis, or scleritis. In patients older than 50 years, giant cell arteritis should be suspected. Patients should be referred immediately to rheumatology if they have other symptoms and signs suggestive of giant cell arteritis.

VII. ANISOCORIA/PTOSIS

Patients with anisocoria could have a benign physiologic anisocoria or a more pathologic condition such as a Horner syndrome (mild ptosis, small pupil) (possible etiologies: carotid dissection, apical lung mass) (Figure 2-4) or involvement of the third cranial nerve (possible etiologies: posterior communicating artery aneurysm, cavernous sinus thrombosis, brainstem stroke) (Figure 2-5) Immediate neurologic referral should be obtained in these situations.

Figure 2-4 Right Horner Syndrome

Figure 2-5 Right Cranial Nerve III Palsy

If a patient presents with ptosis, the possibilities are benign (levator dehiscence, mechanical problem from contact lens use or eye rubbing, congenital) or more serious such as Horner syndrome, involvement of the third cranial nerve, or myasthenia gravis (fatigable ptosis). Again, the suddenness of onset should dictate the speed of referral.

VIII. CASE DISCUSSIONS

Case 2-1. Giant cell arteritis is the most likely etiology for this patient's temporal headache and eye pain since she is older than 50 years. It is very important to ask the patient about jaw claudication, which is present in the majority of patients with giant cell arteritis. Other possible causes for her eye pain would be keratitis, uveitis, or scleritis. The most appropriate management is to start the patient on 60 mg of prednisone daily, arrange for a temporal artery biopsy, and immediately refer the patient to rheumatology.

Case 2-2. In this patient the most important historical point to establish is whether this visual problem is monocular (ocular cause) or binocular (neurologic cause) If the visual disturbance is binocular and since this patient is young, the most likely etiology is migraine aura. Migraine aura can occur either with or without a headache.

IX. CME QUESTIONS

1. A 52-year-old woman suddenly developed a mild drooping of her right eyelid and a smaller pupil on the right. She was in a motor vehicle accident one year prior resulting in chronic neck pain. On the day she comes to the emergency department she notices a sharper than usual right neck pain that resolves by the time of evaluation. What is the most likely cause of this patient's visual problem?

a. Brainstem stroke

b. Myasthenia gravis

c. Physiologic anisocoria

d. Right carotid dissection

2. A 66-year-old man with hypertension and diabetes suddenly develops left-sided ptosis and a right hemiparesis. On examination the left eye is deviated out and down, and there is almost complete ptosis. What is the most likely etiology of this patient's presentation?

a. Basal ganglia hemorrhage

b. Left-sided brainstem stroke

c. Right parietal stroke

d. Subarachnoid hemorrhage

3. A 45-year-old woman develops sudden onset of floaters and flashes in the right eye followed a day later by visual loss that she describes as a veil floating in front of the right eye. What is the likely etiology?

a. Amaurosis fugax

b. Floaters

c. Migraine

d. Retinal detachment

4. A 46-year-old obese woman develops the sudden onset of a severe global headache and notices double vision in most fields of gaze. On examination she has moderate ptosis on the right and no reaction of the right pupil. How would you manage this patient?

a. Imitrex injection for acute migraine

b. Immediate referral to neurosurgery

c. Immediate referral to ophthalmology

d. Lumbar puncture

5. A 60-year-old diabetic man presents with intermittent horizontal double vision when looking to the left for the past month. He has covered each eye alternately and the double vision resolves. He says that the problem is worse in the afternoon when he also notices a droopy right eyelid. What is the most likely etiology for this man's visual problem?

a. Cavernous sinus thrombosis

b. Fourth cranial nerve palsy

c. Myasthenia gravis

d. Thyroid ophthalmopathy

CME Answers

1. d. Right carotid dissection


2. b. Left-sided brainstem stroke


3. d. Retinal detachment


4. b. Immediate referral to neurosurgery


5. c. Myasthenia gravis