The profile of strabismus in stroke survivors

To evaluate the profile of strabismus that occurs in stroke survivors and determine the relationship between site of stroke and symptom of diplopia.

Prospective multi-centre cohort trial involving 16 recruiting centres (Vision In Stroke (VIS) Group). Standardised referral and investigation protocol used by local investigators. Each patient underwent assessment of ocular alignment, motility, and binocular vision. Results were evaluated with non-parametric statistical tests.

In all, 512 patients were recruited with a mean age of 69 years: SD 15 over a 2-year period (59% male patients, 41% female patients). Median duration from onset to vision assessment was 19 days (range 0-1140 days). About 19% of the patients had strabismus detected on orthoptic investigation after the onset of stroke. Of these strabismic patients 12.5% had strabismus that pre-existed the onset of stroke (that could be determined from case history). A total of 70% had strabismus associated with ocular motility abnormalities and 30% were in isolation. About 24% were associated with brain stem, cerebellar, thalamus or basal ganglia strokes, and 73% with cortical strokes. Around 36% complained of diplopia and the remainder had no symptoms related to their strabismus.

Strabismus was found to occur in 16.5% of patients after their stroke. Strabismus with diplopia was always associated with other ocular motility abnormalities, whereas strabismus without associated ocular motility abnormalities did not result in the symptom of diplopia.