Decompensated Superior Oblique Palsy Secondary to Bilateral Nutritional Optic Neuropathy Following Bariatric Surgery

Optic neuropathy can occur secondary to nutritional deficiencies in patients who have undergone bariatric surgery. We present a unique case of a 39-year-old man, claiming to be generally healthy, who presented with intermittent vertical diplopia and bilateral decreased vision in each eye. Visual acuity was 6/18 in the right eye and 6/12 in the left eye. Ishihara testing was defective for both eyes. Automated visual fields showed a severe generalized reduction in sensitivity in both eyes. The patient had a left head tilt and a right intermittent hypertropia of 30 prism diopters in primary position. CT of the orbits revealed a right superior oblique of small caliber. On further questioning, the patient admitted to a history of bariatric surgery 7 years prior to presentation with failure to take any nutritional supplements. Blood work demonstrated deficiencies in folate, thiamine, and copper. Within 6 months of initiating nutritional supplements, the vision in each eye was markedly improved and the diplopia resolved. There was an associated normalization of thiamine and copper, but folate levels remained low. We believe that the nutritional deficiency caused a bilateral optic neuropathy and the resulting vision loss precipitated a manifestation of a congenital superior oblique palsy that had previously just been a phoria. The case emphasizes the importance of considering occult sensory etiologies of acquired strabismus.