gms | German Medical Science

A 46-year-old female patient was referred for complaints of dizziness and balance disturbances lasting as long as 1 year. She had a decompensated esodeviation which had been treated with prisms.

The following examinations were performed: Refractometry, assessment of visual acuity, perimetry, unilateral and alternate prism and cover test, testing of ocular motility and binocular vision, slitlamp biomicroscopy, direct and binocular ophthalmoscopy, cranial computed tomography with contrast agent, and angiography.

The patient had a myopia of -1.0 dpt OD and -2.75 dpt OS. The visual acuity was 1.0 OU. The visual fields were normal. There was a comitant esotropia of 12° at distance fixation in all directions of gaze and 14° at near fixation. Voluntary and visually guided reflexive saccades did not reveal any restriction of the range of both horizotal and vertical eye movements, but there was a gaze-paretic nystagmus in right-gaze. With the squint angle neutralized with prisms, there was normal stereopsis. The anterior segments and the pupillary functions were normal. In both eyes, the optic disc margins were slightly indistinct with a nasal elevation of 1 dpt in the right eye. Computed tomography showed a mass presumably originating from the right cerebellopontine angle with a diameter of 5 cm extending over the right petrosal bone. The ventricle system was plump. The 3^rd ventricle was significantly dilated. After an angiography, the tumor was resected via suboccipital craniotomy. One week after surgery, patient had no complaints. There were still an esophoria of 4° at near fixation and a gaze-holding defect to the right.

Strabismus caused by an intracranial tumor, is not inevitably incomitant. Oculomotor disturbances caused by a slowly growing intracranial tumor can pretend a harmless esophoria. The assessment of ocular motility has to include skillful testing of the gaze-holding in eccentric gaze.