Relationship between Control Grade and Stereoacuity in Basic Intermittent Exotropia

ABSTRACT

PURPOSE: The present study was conducted to identify the correlation between control grade and stereoacuity in basic intermittent exotropia (X[T]). METHODS: Eighty-six patients with basic X (T) were divided into 3 subgroups according to their control grade and the near and distant stereoacuities were evaluated. RESULTS: Group 1; good control group, consisted of 28 patients, group 2; fair control, 30 patients, and group 3; poor control, 28 patients. Mean near stereoacuities measured by the Titmus test were 58.21 arcseconds in group 1, 75.33 arcseconds in group 2, and 151.43 arcseconds in group 3. The mean distant stereoacuities measured by a Mentor B-VAT(R) II-SG videoacuity tester were 118.93 arcseconds in group 1, 165.33 arcseconds in group 2, and 276.43 arcseconds in group 3. When comparing the 3 groups, the poorer the control grade, the worse were the near and distant stereoacuities (p = 0.002, p < 0.001). When compared in pairs, however, group 1 showed a better near stereoacuity than groups 2 and 3 (p = 0.02, p = 0.002, respectively), while group 2 and group 3 did not show any distinct differences (p = 0.13). Group 1 also showed a better distant stereoacuity than groups 2 and 3 (p = 0.02, p < 0.001, respectively), as did group 2 compared to group 3 (p < 0.001). CONCLUSIONS: Control grade and distant stereoacuity have significant correlation in patients with basic X (T) and can function as helpful indicators for monitoring the deterioration and progression of exodeviation.