Table 1

Characteristics of groups A, A1, and B: A1 and B compared by means of an unpaired Student's t test, Mann–Whitney U test, and the χ2 test

 Characteristic Category Group A (n=119) Group A1 (n=69) Group B (n=17) t /Z /χ2 p Value Age (months) mean (SD) 61 (13) 61 (12) 74 (30) Z −0.92 0.36 median 58 58 57 SER (dioptres) df 74 Strabismic 4.0 (2.1) 4.2 (1.9) 3.8 (2.4) t 0.95 0.35 Dominant 2.9 (1.8) 2.8 (1.7) 3.1 (2.1) t 0.73 0.47 Interoc dif 0.9 (1.5) 1.1 (1.7) 0.5 (0.8) t −0.57 0.57 Amblyopia category Strabismic n=65 n=34 n=12 df 1 Mixed n=54 n=35 n=5 χ2 1.65 0.20 Strabismus category Esotropia n=100 n=59 n=15 df 1 Exotropia n=19 n=10 n=2 χ20.001 0.97 BSV BSV 49 abnormal 37 abnormal 6 abnormal df 1 suppression 64 suppression 32 suppression 11 suppression χ2 0.14 0.52 6 inconclusive Fixation Eccentric 90 eccentric 52 eccentric 11 eccentric df 1 Foveal 29 foveal 17 foveal 6 foveal χ2 3.62 0.16 First corrected GAC score (log units) mean (SD) df 74 Strabismic 0.448 (0.272) 0.431 (0.253) 0.504 (0.249) t −0.68 0.50 Dominant 0.903 (0.141) 0.898 (0.118) 0.922 (0.162) t 0.69 0.49 Interoc dif 0.456 (0.263) 0.467 (0.241) 0.418 (0.351) t −1.45 0.15
• t = two tail unpaired Student's ttest, applied for interval data which follows a normal distribution.

• Z = Mann–Whitney U test, non-parametric version oft test applied to interval data with a non-normal distribution.

• χ2 = data categorised by dichotomous scale.

• df = degrees of freedom.

• Interoc dif = interocular difference.

• BSV = binocular single vision; SER = spherical equivalent refraction.