Clinical Usefulness of a Computerized Vision Chart for Distance Stereoacuity Assessment in Children with Intermittent...

The aim of this study is to evaluate distance stereoacuity in children with intermittent exotropia (IXT) using a computerized vision chart (CVC), to compare the results to the normal subjects, and to determine if any correlation between stereoacuity and IXT severity exits.

A prospective case-control study was conducted including 24 children with IXT and 25 age-matched normal subjects. The mean age was 8.9 ± 4.5 in IXT group and 9.4 ± 4.2 in control group. The majority of patients (n = 17) had basic type IXT. Full ophthalmic examinations, deviations and stereoacuity tests were evaluated. Stereoacuity was measured with the CVC for distance stereoacuity and Randot stereotest book for near stereoacuity. Level of fusional control in patients with IXT was assessed using Newcastle Control Score (NCS). Seven of the patients with IXT were also reevaluated postoperatively.

Near stereoacuity was good in both IXT and control groups, and there was no significant difference between groups. There was a poor correlation between near stereoacuity and NCS (r_s = 0.15, p = .48). Distance stereoacuity in the IXT group was significantly reduced compared to controls (p = .004). There was a positive correlation between distance stereoacuity values and NCS in patients with IXT (r_s = 0.73, p < .001).

Diminished distance stereoacuity in children with IXT can be detected with the CVC and this test may be useful for deciding the timing of surgical intervention and postoperative evaluation.