In univariate analysis, the amount of refractive anisometropia increased significantly with older age (
P < 0.001;
β: 0.16; equation of the regression line: Anisometropia (diopters) = 0.03 × Age [years] + 0.09). Refractive anisometropia was significantly higher in girls than in boys (0.38 ± 0.57 diopters versus 0.35 ± 0.56 diopters,
P < 0.001;
Fig. 1). Higher refractive anisometropia was further associated with the systemic parameters of taller body height (
P < 0.001), heavier body weight (
P < 0.001), older paternal age (
P < 0.001), older maternal age (
P < 0.001), higher education of father (
P < 0.001) and mother (
P < 0.001), more time spent indoors reading and writing in a weekday (
P = 0.002) or during a weekend (
P = 0.002), more time spent indoors playing handheld computer games in a weekday (
P = 0.03) or during the weekend (
P = 0.001), less time spent outdoors in a week (total) (
P = 0.001), and shorter sleeping duration time (
P < 0.001) (
Table 1). Higher refractive anisometropia was associated with the ocular parameters of longer axial length (
P < 0.001) and larger intereye difference in axial length (
P < 0.001), greater myopic refractive error (
P < 0.001) (
Fig. 2), longer corneal curvature radius (left eye) (
P = 0.007) and higher intereye difference in corneal curvature radius (
P < 0.001), lower corneal astigmatism (
P < 0.001) and higher intereye difference in corneal astigmatism (
P < 0.001) (
Fig. 3), lower BCVA (
P < 0.001), lower stereoacuity (
P < 0.001) (
Fig. 4), higher prevalence of an abnormal Worth 4-dot test (
P < 0.001), and higher intraocular pressure (
P = 0.008) (
Table 1). Refractive anisometropia was not significantly associated with region of habitation (
P = 0.10), birth length (
P = 0.80) and birth weight (
P = 0.69), perinatal oxygen therapy (
P = 0.48), paternal myopia (
P = 0.18) and maternal myopia (
P = 0.14), writing posture (
P = 0.92), distance between the eyes and book when reading or writing (
P = 0.09), way of holding the pen during writing (
P = 0.92), axis of the corneal astigmatism of the right eye (
P = 0.95) and left eye (
P = 0.12), corneal diameter of right eye (
P = 0.89) and left eye (
P = 0.99), intraocular pressure of the right eye (
P = 0.23), and intereye difference in intraocular pressure (
P = 0.95).