The Assessment of Stereoacuity in Patients with Strabismus

ABSTRACT

PURPOSE: To analyze stereoacuity in patients with strabismus using various stereotests. METHODS: Stereoacuity was assessed in children who were diagnosed with intermittent exotropia or refractive accommodative esotropia using the Titmus stereotest, TNO stereotest, and the Lang II stereotest. Patients with amblyopia or previous ocular surgery were excluded. RESULTS: Ninety-four patients with intermittent exotropia and 36 patients with refractive accommodative esotropia were included; the mean age was 7.2 years. The mean stereoacuity in intermittent exotropia was 143.1+/-207.9 seconds of arc with the Titmus stereotest, 130.2+/-103.7 seconds of arc with the TNO stereotest, and 200.0+/-0.0 seconds of arc with the Lang II stereotest. The mean stereoacuity in refractive accommodative esotropia was 430.3+/-288.6 seconds of arc, 232.5+/-90.0 seconds of arc, and 230.0+/-97.9 seconds of arc, respectively. The absence of stereoacuity was more frequent in patients with refractive accommodative esotropia than in patients with intermittent exotropia, and both groups of patients showed the largest proportion of absent stereopsis with the TNO stereotest. No factor was significant for stereopsis in patients with intermittent exotropia and patients with refractive accommodative esotropia. CONCLUSIONS: Stereoacuity showed various seconds of arc according to the type of stereotest in the same patient. Patients with refractive accommodative esotropia showed lower stereoacuity in all stereotests than patients with intermittent exotropia. TNO stereotests are sensitive enough to detect the absence of stereopsis in patients with strabismus.