Man presents with eye pain and blurred vision

The left eye had a mild relative afferent pupillary defect and a superior paracentral scotoma.

Catherine A. Cox

Jordana F. Goren

A 62-year-old man presented to the New England Eye Center with left eye pain and decreased vision. He initially presented to an outside emergency department with intermittent headache and dull eye pain for 1 week. His symptoms were thought to be secondary to poorly controlled hypertension but did not improve with medical treatment. On evaluation 2 days later, he also complained of blurred vision, which he described as a “veil” over his vision.

Ocular history was significant for myopia, presbyopia and mild cataracts. Medical history was significant for uncontrolled hypertension and a distant history of hepatitis. Current medications included atenolol and lisinopril. Social history was notable for a 40 pack-year history of smoking.

Best corrected visual acuity was 20/20 in the right eye and 20/40 in the left eye. Pupils were reactive; however, a mild relative afferent pupillary defect was present in the left. Ishihara color plates were full in both eyes, although the patient reported significant red desaturation in the left eye. IOP was 12 mm Hg in the right eye and 14 mm Hg in the left eye. Extraocular motility was full; however, the patient reported mild associated pain. Visual field testing showed a superior paracentral scotoma in the left eye. The anterior segment exam was significant for mild cataracts in both eyes. The posterior segment exam was normal in both eyes, including the optic nerve examination (Figure 1).

Figure 1. Fundus photograph demonstrates normal optic nerve head without obvious swelling. Images: Williams SL and Strominger MB

What is your diagnosis?

Eye pain, blurred vision

The differential diagnosis of pain and decreased vision includes optic neuritis of any etiology. With a normal optic nerve examination, retrobulbar optic neuritis becomes more likely. Ischemic optic neuropathy from giant cell arteritis or non-arteritic ischemic optic neuropathy, which is associated with atherosclerosis, diabetes, hypertension, hyperlipidemia and anemia, may cause this picture, but typically there is no pain with ocular motility. Compressive optic neuropathy, such as primary intracranial tumor, metastasis and aneurysm, can present similarly. Acute papilledema may cause a similar picture; however, typically this produces bilateral disc edema with normal color vision, normal visual acuity and no ocular pain with eye movement. Toxic, metabolic and hereditary optic neuropathies should also be considered; however, typically these patients will have bilateral optic nerve head disease, with the exception of Leber’s optic neuropathy, which may initially present unilaterally.

Discussion

Demyelinating optic neuritis is an inflammatory lesion of the optic nerve. Annual incidence in the United States is five in 100,000, occurring most commonly in the 18- to 45-year-old age group. It is often idiopathic (50% of cases), but it is commonly associated with neuro-inflammatory diseases (eg, multiple sclerosis, neuromyelitis optica) and less frequently with granulomatous inflammatory disorders (eg, sarcoidosis, Wegener’s granulomatosis) or infectious causes (eg, tuberculosis, syphilis, herpes simplex virus). Common presenting symptoms include rapidly progressive onset of blurred vision, decreased color vision and ocular pain worse with eye movement. Patients may also complain of abnormal sensation associated with objects moving back and forth (Pulfrich phenomenon) and may have worsening symptoms with an increase in body temperature (Uhthoff’s phenomenon). Symptoms are typically unilateral in adults and bilateral in children. Symptoms peak in days to weeks, usually with improvement by 8 to 10 weeks. Recurrence of optic neuritis is common.

Diagnosis and management

Examination of patients with typical demyelinating optic neuritis may reveal a relative afferent pupillary defect in unilateral or asymmetric cases, decreased color vision, and central, cecocentral, arcuate or altitudinal visual field defects. Optic nerve head swelling is seen at the onset of symptoms in roughly 33% of patients, with a normal-appearing disc in 66% of patients. MRI with contrast and fat suppression is the modality of choice for identifying optic nerve inflammation, as well as other inflammatory lesions, vascular lesions and tumors. Cerebrospinal fluid may also be helpful diagnostically, especially in atypical cases or when neuro-inflammatory disease or central nervous system infection is suspected. Although patients may have associated white matter brain lesions with idiopathic disease, they are at significantly higher risk for multiple sclerosis if there are multiple, ovoid white matter lesions, particularly in the region of the corpus callosum.

The Optic Neuritis Treatment Trial demonstrated that treatment with IV steroids hastens visual recovery, although there is no significant improvement in final visual outcome. Treatment with oral steroids, however, may increase the risk of recurrence and the risk of progression to multiple sclerosis, so it is generally avoided. Treatment typically consists of methylprednisolone 1 g/day IV for 3 days followed by an oral prednisone taper.

In our patient, MRI scan of the brain and orbits revealed focal, retrobulbar inflammation of the left optic nerve (Figures 2a and 2b). There were no associated white matter lesions, vascular lesions or masses. Laboratory studies were negative for infectious and inflammatory causes of optic neuritis, including evaluation of cerebrospinal fluid. The patient was treated with IV methylprednisolone, followed by an oral prednisone taper, with resolution of his symptoms. This patient is somewhat unusual in that he is older than the average patient with typical optic neuritis. Therefore, we will follow him closely and consider follow-up MRI and possible testing for neuromyelitis optica in the future.

Figures 2a and 2b. MRI scan of the brain and orbits with gadolinium and fat suppression demonstrates a focal inflammatory lesion of the left optic nerve. There were no associated white matter lesions of the brain.

References:

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• Steven L. Williams, MD, and Mitchell B. Strominger, MD, can be reached at New England Eye Center, Tufts University School of Medicine, 750 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; website: www.neec.com.

• Edited by Catherine A. Cox, MD, and Jordana F. Goren MD, MS. Drs. Cox and Goren can be reached at New England Eye Center, Tufts University School of Medicine, 750 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; website: www.neec.com.