BACKGROUND: Some patients with acquired horizontal gaze palsy overcome the adduction palsy by utilizing convergence. This substitution phenomenon is very rare. We report a patient with horizontal gaze palsy who was able to use convergence to compensate for the lack of adduction in the left eye. CASE: The patient was a 31-year-old woman with an arteriovenous malformation in the fourth ventricle. She suffered right gaze palsy and right abducens palsy after tumor surgery and radiation therapy. OBSERVATIONS: Three years after the vascular accident, she was found to be able to adduct the left eye, in association with the adduction of the right eye. At the same time, constriction of both pupils and globe retraction of the left eye were observed. When she shifted the gaze direction of her left eye from left to right, an 11 and 8 diopter increase of myopia in the right and left eyes, respectively, was confirmed by objective refractometry. CONCLUSIONS: The existence of convergence substituting for adduction in this patient with horizontal gaze palsy was confirmed by refraction change in addition to pupillary change.
BACKGROUND: Some patients with acquired horizontal gaze palsy overcome the adduction palsy by utilizing convergence. This substitution phenomenon is very rare. We report a patient with horizontal gaze palsy who was able to use convergence to compensate for the lack of adduction in the left eye. CASE: The patient was a 31-year-old woman with an arteriovenous malformation in the fourth ventricle. She suffered right gaze palsy and right abducens palsy after tumor surgery and radiation therapy. OBSERVATIONS: Three years after the vascular accident, she was found to be able to adduct the left eye, in association with the adduction of the right eye. At the same time, constriction of both pupils and globe retraction of the left eye were observed. When she shifted the gaze direction of her left eye from left to right, an 11 and 8 diopter increase of myopia in the right and left eyes, respectively, was confirmed by objective refractometry. CONCLUSIONS: The existence of convergence substituting for adduction in this patient with horizontal gaze palsy was confirmed by refraction change in addition to pupillary change.