Table 3. Independent risk factors^* for inter-ocular visual acuity difference of two or more lines in preschool children in the Multi-Ethnic Pediatric Eye Disease Study and Baltimore Pediatric Eye Disease Study.

Variable	OR (95% CI)	P value
SE anisometropia		<0.0001
<0.5 D (reference)	1.0
0.5 to <1.0 D	1.50 (1.06 – 2.11)
1.0 to <2.0 D	4.48 (2.75 – 7.32)
≥2.0 D	39.76 (19.59 – 80.71)
Strabismus		<0.0001
No horizontal strabismus	Reference
Exotropia	1.23 (0.45 – 3.30)
Esotropia	8.98 (5.18 - 15.54)
Race/ethnic group		<0.0001
Non-Hispanic White	Reference
African-American	0.97 (0.64 – 1.46)
Hispanic	2.05 (1.37 – 3.06)
J45 anisometropia		<0.0001
<0.25 D	Reference
0.25 to <0.5 D	1.60 (1.10 – 2.32)
0.5 to <1.0 D	2.24 (1.37 – 3.66)
≥ 1.0 D	6.69 (2.91 – 15.41)
Age group (in months)		0.0002
60-72	Reference
48-59	1.12 (0.76 - 1.63)
36-47	2.05 (1.44 - 2.92)
30-35	1.61 (0.94 – 2.76)
J0 anisometropia		0.0004
<0.25 D	Reference
0.25 to <0.50 D	1.49 (1.02 – 2.17)
0.50 to <1.00 D	2.36 (1.33 – 4.19)
≥ 1.00 D	5.31 (1.81 – 15.63)
Study site		0.0006
MEPEDS	Reference
BPEDS	0.45 (0.29 – 0.71)

IOD: inter-ocular visual acuity difference of 2 or more lines with visual acuity 20/32 or worse in the worse eye. SE: spherical equivalent. D: diopters. J0: J0 (Cartesian) power vector component of astigmatism. J45: J45 (oblique) power vector component of astigmatism. MEPEDS: Multi-Ethnic Pediatric Eye Disease Study. BPEDS: Baltimore Pediatric Eye Disease Study. OR: Odds ratio. 95%CI: 95% confidence interval.

^*Based on a multivariate step-wise logistic regression model.