A Unique Case of Psychogenic Binocular Diplopia

Diplopia is a common chief complaint in the ophthalmology clinic, and it is important to differentiate diplopia requiring urgent work-up versus benign forms of diplopia that can be managed conservatively. This case demonstrates a 39-year-old male who reported the ability to move each eye independently resulting in chronic binocular diplopia. He reported having an extensive work-up done by an outside ophthalmologist that returned unremarkable. His glasses on presentation had a mild myopic correction in both eyes (OU), 1.50 prism diopters (PD) base up (BU) in the right eye (OD), and 0.50 PD BU in the left eye (OS), which helped intermittently-but not completely-resolve his diplopia. On presentation, his visual acuity (VA) was 20/20 OU with correction. He had a normal sensorimotor exam, including being orthotropic in primary gaze, having full motility OU, having normal saccades OU, and having no nystagmus OU. The patient voluntarily moved his eyes in a rhythmic sequence of convergence ➔ left gaze ➔ convergence ➔ right gaze ➔ convergence ➔ repeat. This sequence can initially appear to exhibit independent movement of each eye when done rapidly, but close examination can expose it as simple voluntary ductions and vergences that fall within the domain of normal ocular motility. With proper education, reassurance, and follow-up, the patient's subjective visual disturbances improved. Prompt recognition of this motility sequence can result in favorable visual improvements and avoidance of unnecessary work-up.