Retinal Review, Issue 26
CASE NUMBER 26
A 17 year old girl was referred for vision loss in her left eye. She noted the problem one year before. At that time she had some vision in the eye, but it continued to worsen as the year progressed. She was busy with her studies and did not report her vision loss to her parents. Past ocular history is negative. Past medical history is also negative. The patient was born in India and emigrated to America at age 8. She was referred for unexplained vision loss in her left eye.
On examination, visual acuity was OD: 20/20 and OS: LP. IOPs were normal. The anterior segments were normal. A 2+ APD was present OS. The lens and vitreous were clear OU. Dilated examination of the right eye was unremarkable; the left optic nerve was pale and atrophic and the left retina was normal:
The patient was diagnosed with left optic neuropathy. Differential diagnosis includes demyelination (optic neuritis), compression, previous vascular event such as central retinal artery or vein occlusion, optic nerve ischemia, optic nerve inflammation, hereditary optic nerve disease such as Leber’s Hereditary Optic Neuropathy, toxic optic neuropathy, or acquired optic neuropathy from trauma or vitamin deficiency. To continue our evaluation, we performed a visual field test and the results were both intriguing and helpful. We assumed that the pathology was all in the left eye. The left visual field due to the LP vision was not obtainable. To our surprise, there was a subtle but definite superotemporal visual field defect in the right eye. This allowed us to focus our interest on the optic chiasm. Patients with chiasmal lesions such as pituitary tumors typically have symmetric bitemporal visual field defects. If the tumor is in the posterior chiasm, the defect is more commonly bitemporal scotomas rather than full field defects. If the lesion is in the anterior chiasm it typically causes central and profound vision loss in one eye as it compresses both the anterior chiasm and the optic nerve before the chiasm, and a superotemporal visual defect on the contralateral side due to compression of Willbrand’s knee. We were fairly convinced that our patient had anterior chiasmal syndrome with compression of the left optic nerve and the nasal fibers of the right eye prior to decussation. This is usually due to a chiasmal tumor and less likely due to demyelination. We scheduled the patient for an MRI of the chiasm with contrast.
The MRI demonstrated a large anterior chiasmal lesion with a cystic component. The lesion compressed the chiasm and the left optic nerve anterior to the chiasm. As per the neuroradiologist, the most likely lesion is an epidermoid cyst, an unusual intracranial lesion. The patient is scheduled for neurosurgical removal with the hope that the mass can be completely removed. As opposed to optic nerve disease due to ischemia, the optic nerve can recover some function after a compressive lesion is removed. In fact there are numerous cases of complete resolution of bitemporal visual field defects after removal of pituitary tumors. It is unlikely that the left eye will have significant recovery due to the chronicity of the condition, but we will retest both eyes after surgery.
DR. BURTON WISOTSKY
DR. GEORGE VELIKY (ISELIN OFFICE)
DR. MIKE VELIKY (ROCHELLE PARK OFFICE)
DR. ALLISON LAFATA (WEST ORANGE OFFICE)
DR. JOHN INSINGA (PARSIPPANY OFFICE)
DR. KATHERINE MASTROTA (NEW YORK OFFICE)
ANN LACEY (MARKETING DIRECTOR)