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patients who may otherwise appear to have minimal ocular or adnexal trauma (“white-eyed” fracture). Examination of the extraocular muscles reveals restrictive deficits and diplopia at gaze opposite the fracture. CT scan of the orbits may reveal a fracture with entrapped muscle, but this may be easily missed. This type of fracture with muscle entrapment requires urgent surgical repair as ischemic damage and fibrosis of the muscle may occur if not treated promptly.

30.In facial trauma involving orbital fractures, what are indications for repair?

Emergent repair is indicated for globe luxation into the maxillary sinus or if an oculocardiac reflex is observed. Urgent repair is recommended for muscle entrapment due to trapdoor fractures. Repair within 1 to 2 weeks is often suggested in patients with sustained diplopia due to nontrapdoor entrapment, early enophthalmos of more than 3 mm, significant hypoglobus, large orbital wall fractures that will probably cause enophthalmos, or associated rim or other facial fractures.

Indications for observation without treatment include lack of or improving diplopia or entrapment, lack of enophthalmos, and small fractures with low risk of future enophthalmos.

Bibliography

Bagheri A, Babsharif B, Abrishami M, Salour H, Aletaha M: Outcomes of surgical and non-surgical treatment for sixth nerve palsy, J Ophthalmic Vis Res 5(1):32–37, 2010.

Bellusci C: Paralytic strabismus, Curr Opin Ophthalmol 12:368–372, 2001.

Bradfield YS, Struck MC, Kushner BJ, Neely DE, Plager DA, Gangnon RE: Outcomes of Harada-Ito surgery for acquired torsional diplopia, J AAPOS 16(5):453–457, 2012.

Burde RM, Savino PJ, Trobe JD: Clinical decisions in neuro-ophthalmology, ed 3, St. Louis, 2002, Mosby.

Brazis PW, Masdeu JC, Biller J: Localization in clinical neurology, ed 6, Philadelphia, 2011, Lippincott Williams & Wilkins. Elrod RD, Weinberg DA: Ocular myasthenia gravis, Ophthalmol Clin North Am 17(3):275–309, 2004.

Fakiri MO, Tavy DL, Hama-Amin AD, Wirtz PW: Accuracy of the ice test in the diagnosis of myasthenia gravis in patients with ptosis, Muscle Nerve 48(6):902–904, 2013.

Golnik KC, Pena R, Lee AG, Eggenberger ER: An ice test for the diagnosis of myasthenia gravis, Ophthalmology 106(7):1282–1286, 1999.

Hamilton SR: Neuro-ophthalmology of eye-movement disorders, Curr Opin Ophthalmol 10(6):405–410, 1999. Harada M, Ito Y: Surgical correction of cyclophoria, Jpn J Ophthalmol 8:88–92, 1964.

Holmes JM, Beck RW, Kip KE, et al.: Botulinum toxin treatment versus conservative management in acute traumatic sixth nerve palsy or paresis, J AAPOS 4(3):145–149, 2000.

Jordan DR, Mawn L: Blowout fractures of the orbit. In Black EH, Nesi FA, Calvano CJ, Gladstone GJ, Levine MR, editors: Smith and Nesi’s Ophthalmic Plastic and Reconstructive Surgery, ed 3, New York, NY, USA, 2012, Springer Science, pp 243–263.

Karmani TA, Schmidt J, Crowson CS, Ytterberg SR, Hunder GG, Matterson EL, Warrington KJ: Utility of erythrocyte sedimentation rate and C-reactive protein for the diagnosis of giant cell arteritis, Semin Arthritis Rheum 41(6):866–871, 2012.

Larner AJ: False localizing signs, J Neurol Neurosurg Psychiatry 74(4):415–418, 2003.

Larner AJ, Thomas JD: Can myasthenia gravis be diagnosed with the “ice pack test”? A cautionary note, Postgrad Med J 76:162–163, 2000.

Li Y, Arora Y, Levin K: Myasthenia gravis: newer therapies offer sustained improvement, Cleve Clin J Med 80(11):711–721, 2013.

Mein J, Trimble R: Diagnosis and management of ocular motility disorders, ed 2, London, 1991, Blackwell Scientific Publications.

Miller NR, Newman NJ: Walsh and Hoyts’ clincal neuro-ophthalmology, ed 6, Baltimore, 2005, Williams & Wilkins. North American Neuro-Ophthalmology Society: www.nanosweb.org.

1.What is optic neuritis?

Optic neuritis is any inflammation of the optic nerve. It may be idiopathic or associated with systemic disease.

2.Which systemic diseases are associated with optic neuritis?

The most common disease associated with optic neuritis is multiple sclerosis (MS). However, neuromyelitis optica, syphilis, sarcoidosis, Lyme disease, and other collagen vascular diseases such as Wegener’s granulomatosis and systemic lupus erythematosus are less commonly associated.

3.Who most commonly gets optic neuritis?

Women between the ages of 15 and 45 years are most commonly affected.

4.What are the typical clinical findings in optic neuritis?

Optic neuritis causes acute or subacute visual loss that is preceded or accompanied by pain on eye movement and that may progress over 10 to 14 days. Visual acuity may range from 20/20 to no light perception. However, even if visual acuity is 20/20, the patient usually has a defect in color vision, contrast sensitivity, and visual field. If the neuritis is unilateral, an afferent pupillary defect is present. The optic disc may be normal or swollen.

5.Which clinical test is most sensitive for patients with optic neuritis?

The most sensitive test—that is, the test most likely to be abnormal in a patient with optic neuritis— is contrast sensitivity.

6.How common is pain on eye movement in patients with optic neuritis?

Pain around the eye or pain exacerbated with eye movement was present in 92% of patients in the Optic Neuritis Treatment Trial (ONTT).

7.What visual field defects are found in patients with optic neuritis?

The classic visual field defect in optic neuritis is central scotoma. However, results of the ONTT showed that any optic nerve visual field defect is compatible with optic neuritis, including altitudinal defects and arcuate defects as well as diffuse visual field defects.

8.What is the natural history of optic neuritis?

The visual loss of optic neuritis may progress over 10 to 14 days. At that point it should stabilize and shortly thereafter begin to improve.

9.What is the expected visual outcome for patients with optic neuritis?

The ONTT found that at 12 months, 93% of patients were 20/40 or better, 69% were 20/20 or better, and 3% were 20/200 or worse. At 10 years, 91% of patients had acuity of 20/40 or better and 74% were 20/20. At 15 years, 66% had visual acuity of 20/20 or better in both eyes. On average, visual acuity was worse in those who developed MS.

10.Are there any predictors of poor visual outcome?

The ONTT found that the only predictor for poor visual outcome was poor visual acuity at presentation. Nevertheless, all patients with an initial visual acuity of 20/200 or less showed some improvement. However, 5% of the patients were still 20/200 or less at 6 months.

11.What were the objectives of the ONTT?

The ONTT was a multicenter, randomized, prospective clinical trial to determine whether corticosteroid treatment of optic neuritis was beneficial for visual outcome. A secondary objective was to determine the risk of developing MS in patients with optic neuritis. The patients who participated in the ONTT were randomized to three treatment arms. One group of patients received oral placebo; one group received oral prednisone, 1 mg/kg for 14 days; and one group received intravenous (IV) methylprednisolone (Solu-Medrol), 250 mg every 6 hours for 3 days, followed by oral prednisone, 1 mg/kg for 11 days.

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12.What were the conclusions of the ONTT regarding treatment of optic neuritis?

No treatment group had statistically significantly better visual acuity at 6 months. However, patients treated with IV methylprednisolone began to recover vision more quickly. The surprising result was that patients treated with oral prednisone, 1 mg/kg for 14 days, had an increased incidence (2×) of recurrence of optic neuritis in the affected or contralateral eye. The researchers concluded that oral prednisone at a dose of 1 mg/kg is contraindicated in the treatment of optic neuritis.

13.What was the strongest predictor for the development of MS?

An abnormal magnetic resonance imaging (MRI) scan (Fig. 31-1) was the strongest predictor for development of clinically definite MS at 2 years. Placebo-treated patients whose MRI scan at study entry showed two or more periventricular white matter lesions >3 mm had a 36% chance of developing MS within 2 years. Patients with one lesion had a 17% chance, and patients with no signal abnormalities had only a 3% chance.

14.What were the other predictors for developing MS?

Previous optic neuritis in the fellow eye, previous nonspecific neurologic symptoms, race (white), and family history of MS were associated with an increased risk of developing MS. Although young age and female gender have been reported to be risk factors for MS, they were not shown to increase the risk within 2 years in the ONTT.

15.What were the conclusions of the ONTT about the effect of treatment on the risk of developing MS?

The results of the ONTT showed that IV methylprednisolone significantly decreased the risk of developing MS at 2 years. Most of the beneficial effect was seen in patients with abnormal MRI scans, because patients with normal MRI scans had a low incidence of MS, regardless of treatment. Among patients with two or more signal abnormalities on MRI, MS developed in 36% treated with placebo, 32% treated with prednisone, and 16% treated with IV methylprednisolone. Thus, the risk of developing MS at 2 years was cut in half by treatment with IV methylprednisolone. After 2 years, the beneficial effect seemed to wear off, and at 3 years and beyond the three groups had a similar incidence of MS.

16.What is the 15-year risk of developing MS after optic neuritis?

A total of 50% of patients enrolled in the ONTT developed MS in a 15-year period. White matter lesions on MRI were the most potent predictor of MS. Patients with one or more lesions had an incidence of MS of 72%. Those with no lesions on MRI had a 25% incidence of MS.

Figure 31-1.  Abnormal MRI in a patient with multiple sclerosis. Classic periventricular white matter lesions appear bright on T2-weighted image.

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KEY POINTS: OPTIC NEURITIS

1. Optic neuritis causes vision loss that may progress over 10 to 14 days. 2. Pain is present in more than 90% of patients with optic neuritis.

3. A total of 93% of patients with optic neuritis will recover vision of 20/40 or better.

4. Patients with at least one white matter lesion on MRI scan have a 72% chance of developing MS at 15 years.

17.What is the 10-year risk of recurrence of optic neuritis?

A total of 35% of patients in the ONTT who completed the examination at 10 years had a documented recurrence of optic neuritis in the previously affected eye or an attack in the fellow eye. Patients who had a diagnosis of MS had a higher recurrence rate (43%) than those who did not have MS (24%).

18.Are there any other medications that may influence the risk of developing MS?

Numerous medications approved for the treatment of MS have been shown to decrease the progression to MS in patients with optic neuritis. The first study was the Controlled High-Risk Subjects Avonex

Multiple Sclerosis Prevention Study, which was a randomized double-blind trial to determine whether treatment with interferon β-1a (Avonex) would affect the risk of developing MS in patients who have a first demyelinating event involving the optic nerve, spinal cord, brain stem, or cerebellum. The patients studied had an acute demyelinating event and an MRI that demonstrated two or more lesions 3 mm or larger in diameter, at least one of which was periventricular or ovoid. All patients were treated with 1 g intravenous methylprednisolone for 3 days, followed by an oral prednisone taper. They were then randomized to receive weekly intramuscular injections of Avonex or placebo. The results demonstrated that at 3 years the probability of developing clinically definite MS was significantly lower in the patients treated with Avonex (35%) than in patients receiving placebo (50%). Similar findings occurred with Betaseron (BENEFIT study), Rebif (ETOMS study), Copaxone (PreCISe study), and now an oral agent—Aubagio (TOPIC study).

19.Describe the appropriate workup and treatment for patients with optic neuritis.

Patients presenting with optic neuritis should have an MRI scan of the brain and orbits. Almost all patients will have enhancement of the optic nerve on the orbital MRI. If the brain MRI scan is normal, no further workup is warranted and sequential follow-up is indicated. If the brain MRI shows white matter lesions consistent with demyelination, the patient should be offered treatment with IV methylprednisolone and should be referred to a neurologist to discuss treatment with one of the immune-modulating agents noted above. The ONTT found no significant benefit in obtaining blood tests for antinuclear antibody or fluorescent titer antibody in patients with typical optic neuritis and no other signs of collagen vascular disease.

20.When do I consider neuromyelitis optica?

Neuromyelitis optica (NMO; Devic’s disease) is a distinct condition that used to be considered a variant of MS. It presents with recurrent and bilateral optic neuritis and transverse myelitis. It should be considered in patients with bilateral optic neuritis, sequential or early recurrence of optic neuritis, or poor recovery of optic neuritis. Other features include transverse myelitis with a lengthy spinal cord lesion (three segments, e.g., C3 to C6) and a brain MRI with little demyelinating activity. It is associated with a positive NMO (anti-aquaporin 4) antibody test, which is now commercially available.

21.Why diagnose neuromyelitis optica? Is it different from multiple sclerosis?

NMO is treated differently, with various immunosuppressants. The interferons, a mainstay of MS treatment, do not help and may even worsen NMO.

Bibliography

Beck RW, Cleary PA, Anderson Jr MM, et al.: A randomized, controlled trial of corticosteroids in the treatment of acute optic neuritis, N Engl J Med 326:581–588, 1992.

Beck RW, Clearly PA, Trobe JD, et al.: The effect of corticosteroids for acute optic neuritis on the subsequent development of multiple sclerosis, N Engl J Med 329:1764–1769, 1993.

Jacobs LD, Beck RW, Simon JH, et al.: Intramuscular interferon beta-1a therapy initiated during a first demyelinating event in multiple sclerosis, N Engl J Med 343:898–904, 2000.

Optic Neuritis Study Group: Multiple sclerosis risk after optic neuritis final optic neuritis treatment trial follow-up, Archiv Neurol 65(6):727–732, 2008 June.

Optic Neuritis Study Group: Visual function 15 years after optic neuritis: a final follow-up report from the optic neuritis treatment trial, Ophthalmology 115(6):1079–1082.e5, 2008 June.

Yanoff M, Duker Duker JS: Ophthalmology: expert consult, ed 4, Philadelphia, 2013, Elsevier.

http://ophthalmologyebooks.com

1.A young woman complains of headaches. Her vision is 20/20 in each eye with no evidence of afferent pupillary defect. She has a bitemporal visual-field cut. What do you suspect?

Suspect a chiasmal lesion. Schedule a magnetic resonance imaging (MRI) scan to make an evaluation.

2.What may simulate a bitemporal field defect?

A bitemporal field defect may be simulated by sector retinitis pigmentosa, coloboma, or a tilted disc.

3.A patient has 20/20 vision in her right eye and 20/400 in her left eye. Her left eye has an afferent pupillary defect and decreased color plates. What should you evaluate in her right eye?

Check visual fields in both eyes. A central scotoma in one eye may be accompanied by a superior temporal field loss in the other. This condition, called a junctional scotoma, is also found in chiasmal lesions. See the chapter on visual fields (Chapter 6).

KEY POINTS: DIFFERENTIAL DIAGNOSIS OF CHIASMAL VISUAL DEFECTS

1. Pituitary lesion—tumor or apoplexy

2.Craniopharyngioma

3.Meningioma

4.Glioma

5.Aneurysm

6.Trauma

7.Infection

4.Is there a difference in the treatment of secreting and nonsecreting symptomatic pituitary tumors?

Yes. A prolactinoma secretes prolactin and may be treated successfully with bromocriptine. A nonsecreting tumor probably requires surgery. Of course, an endocrinologist should fully evaluate the patient for other hormonal imbalances.

5.What visual field is often seen in a toxic or metabolic optic neuropathy?

Bilateral central or centrocecal scotomas. Optic nerves show temporal pallor (Fig. 32-1). Alcohol,

tobacco, and vitamin B12 deficiency, as well as drugs such as chloramphenicol, ethambutol, digitalis, chloroquine, and isoniazid, have been implicated. Check for heavy metals and order a complete

blood count as well as serum levels of vitamins B11, B12, and folate. Consider Leber’s hereditary optic neuropathy as a diagnosis.

6.A 60-year-old man presents with gradual vision loss to 20/400 in his right eye. On examination, the right optic nerve is pale and dot-and-blot retinal hemorrhages are seen. The left eye is normal. What history may be helpful?

A history of radiation treatment. The patient reports radiation to his right frontal sinus 3 years earlier. There is no treatment for radiation optic neuropathy. Panretinal photocoagulation for neovascular disease and anti-vascular endothelial growth factor treatment is used for radiation retinopathy.

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A B

C

Figure 32-1.  Fundus views reveal mild temporal optic disc pallor in right optic disc A, and left optic disc B. More inter­ esting in B, however, is the loss of the nerve fiber layer in the papillomacular bundle. This patient, who had tobacco–­ alcohol amblyopia (mixed toxic and nutritional deficiency optic neuropathy), also had a visual acuity of 20/400 in each eye, which recovered to only 20/100 after changes in habit and diet and vitamin therapy. In this class of optic neuropathies, relatively severely compromised visual acuity and dyschromatopsia often are found with minimal optic disc atrophy. (From Sadun AA, Gurkan S: Hereditary, nutritional, and toxic optic atrophies. In Yanoff M, Duker JS [eds]:

Ophthalmology, ed 2, St. Louis, Mosby, 2004, 1275–1278.) C, Visual field exam reveals centrocecal scotoma. A lesion of the papillomacular bundle (nerve fiber layer or optic nerve) is the usual cause of this defect. (From Burde RM, Savino PJ, Trobe JD: Unexplained visual loss. In Burde RM, Savino PJ, Trobe JD [eds]: Clinical Decisions in Neuro-Ophthalmology, ed 3, St. Louis, Mosby, 2002, pp 1–26.)

7.What may cause a constricted visual field?

•Retinitis pigmentosa

•End-stage glaucoma

•Thyroid ophthalmopathy

•Optic nerve drusen

•Vitamin A deficiency

•Occipital strokes

•Panretinal photocoagulation

•Hysteria

•Malingering

8.How do you differentiate hysteria and malingering from real disease?

Have the patient do a tangent screen at two different distances. The closer the patient stands, the smaller the field should be. In a patient with nonphysiologic visual loss, the fields are often of equal size. Patients also may demonstrate spiraling with kinetic visual-field testing (see Chapter 6).

9.A 55-year-old man notices that the vision in his left eye has worsened suddenly. He has 20/30 vision in his right eye and 20/100 in his left eye. The left eye also shows an afferent pupillary defect and decreased color plates. Visual-field examination reveals an inferior altitudinal defect on the left with a normal full field on

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Table 32-1.  Nonarteritic and Arteritic Ischemic Optic Neuropathy

the right. On fundus examination, the left optic nerve appears pale and swollen superiorly. What is your concern?

An altitudinal defect is a classic finding with ischemic optic neuropathy (ION). The two types are arteritic and nonarteritic (see Table 32-1). Because they are treated differently, you must differentiate the two. First, it is important to ask about symptoms of giant cell arteritis, such as weight loss, anorexia, fever, jaw claudication, headache, scalp tenderness, and proximal joint and muscle

pain. Check for a palpable, tender, nonpulsatile temporal artery. Immediately order an erythrocyte sedimentation rate (ESR), a C-reactive protein (CRP), and a platelet count if you believe that giant cell arteritis is a consideration. The upper limits of normal for an ESR is age divided by 2 for men and age +10 divided by 2 for women. The CRP is not affected by age and may be more sensitive than ESR. However, both are nonspecific tests; any inflammatory process can elevate them. Temporal arteritis patients have elevated platelet counts.

The patient denied any of the symptoms, and his ESR was 20. He was diagnosed with nonarteritic ION. Because 50% of these patients have cardiovascular disease, diabetes, and/or hypertension, he was sent to his internist. He was told that his prognosis for significantly improved vision was low.

Forty percent of patients may have a mild improvement in vision over 6 months. However, some patients note an initial decrease in visual acuity and field, which is followed by a second decrease in visual acuity or field days to weeks later. Unfortunately, there is no proven treatment. A study showed no improvement with optic nerve sheath decompressions. With time, the patient’s optic nerve should atrophy in the area of damage. He has a 35% risk of involvement of the other eye.

10.An 80-year-old man presents with the same history of sudden vision loss and the same visual field as the man in question 9. However, his vision consists of counting fingers at 10 feet, and his optic nerve is pale and swollen with flame-shaped hemorrhages. He admits to jaw pain when he chews, weight loss of 10 pounds, and difficulty in getting up from a chair. He has a tender temporal artery without pulses. His ESR is 120. What do you do?

First, you make a diagnosis of giant cell arteritis and place him on 250 mg of methylprednisolone intravenously every 6 hours for 12 doses, followed by 80 to 100 mg/day of prednisone orally for

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19.How do you differentiate between papilledema and pseudopapilledema?

Pseudopapilledema is not true disc swelling. The vessels surrounding the disc are not obscured, the disc is not hyperemic, and the peripapillary nerve fiber layer is normal. Spontaneous venous pulsations, if present, strongly suggest pseudopapilledema. Nerve fiber layer hemorrhages are not present in pseudopapilledema. Causes of pseudopapilledema include optic nerve drusen and congenitally anomalous discs.

20.What do you do after the evaluation?

You must emergently evaluate the patient for increased intracranial pressure. First, she needs a CT or MRI of the head and orbit to rule out a mass. Provided the scan is normal, a lumbar puncture should follow. If the only abnormality is an increased opening pressure, the diagnosis is pseudotumor cerebri (Fig. 32-2), also known as idiopathic intracranial hypertension.

21.How should the patient be treated?

If she has no optic nerve damage on visual fields, encourage her to lose weight. If the headaches continue or she has evidence of decreased visual acuity or visual-field loss, treatment is indicated. Medications include a diuretic, such as acetazolamide, or systemic steroids. Optic nerve sheath decompression is used for worsening visual fields, and lumboperitoneal shunts have been used for headaches. The intraocular pressure should be treated if elevated.

KEY POINTS: CAUSES OF PSEUDOTUMOR CEREBRI

1.Obesity

2.Pregnancy

3. Drug use: Steroids (use or withdrawal), oral contraceptives, nalidixic acid, tetracycline, vitamin A

4.Idiopathic disease

22.Why did the patient have double vision?

Increased intracranial pressure may cause sixth-nerve palsies.

23.A mother brings in her firstborn for his first exam. He is 6 months of age and appears not to see well. Dilated exam reveals optic nerve hypoplasia. What is the differential diagnosis?

Optic nerve hypoplasia (Fig. 32-3) seems to occur in the firstborn of young mothers who may have diabetes or who may have used lysergic acid diethylamide (LSD), phenytoin, or alcohol during pregnancy. Patients also may have optic nerve hypoplasia in association with Goldenhar’s syndrome or septo-optic dysplasia of de Morsier. The latter patients have seesaw nystagmus and chiasmal anomalies. Because of the risk of growth retardation, diabetes insipidus, and other pituitary abnormalities, patients with optic nerve hypoplasia should have a scan of the optic chiasm and an endocrine evaluation.

Figure 32-2.  Developed papilledema. This is the optic disc of a 30-year-old woman who suffered headaches and blurred vision for 2 months. Disc edema is fully developed. Note the engorged veins and peripapillary hemorrhages. (From Brodsky MC: Congenital optic disc anomalies. In Yanoff M, Duker JS [eds]: Ophthalmology, ed 2, St. Louis, Mosby, 2004, pp 1255–1258.)

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24.A patient has a bilateral, right-sided superior field defect. Where do you suspect the lesion is located?

A “pie-in-the-sky” defect is located in the temporal lobe. The inferior fibers loop around the temporal lobe (Meyer’s loop).

25.What other symptoms may the patient have?

Formed hallucinations, déjà vu experiences, or uncinate fits.

26.What if the patient has a bilateral, inferior right-sided visual-field loss?

This “pie-on-the-floor” defect is typical for the parietal lobe. Patients have spasticity of conjugate gaze and optokinetic nystagmus abnormalities.

27.A patient presents with the visual field illustrated in Figure 32-4. Where is the lesion located?

It is in the right occipital lobe. The more congruous the defect, the more posterior its location. In addition, the nasal retina is larger and allows a temporal crescent in the visual field in the contralateral eye. Macular sparing or splitting also may occur.

28.What else may the patient experience?

Patients with occipital lobe lesions often do not experience other neurologic abnormalities. If they do, they may have unformed hallucinations, dyschromatopsia, prosopagnosia, and alexia without agraphia.

29.What causes pseudo–Foster Kennedy syndrome?

Pseudo–Foster Kennedy syndrome is optic atrophy with contralateral optic disc edema. A frontal lobe tumor causes true Foster Kennedy syndrome. The pseudosyndrome is usually the result of an acute ischemic optic neuropathy in one eye with contralateral atrophy caused by a past episode of the same process. An olfactory groove meningioma also may cause the pseudosyndrome.

Figure 32-3.  Hypoplasia of the left optic nerve. Note the double ring sign. (From Sadun AA: Differentiation of optic nerve from retinal macular disease. In Yanoff M, Duker JS [eds]: Ophthalmology, ed 2, St. Louis, Mosby, 2004, pp 1253–1254.)

Figure 32-4.  Left homonymous hemianopia with temporal crescent in left eye.