The prevalence of anisometropia (A
cycl > 1 D) in the whole study population was 19.3% compared with 18.5% for A
subj. Median severity for both A
cycl and A
subj was 0.37 D (0.12–0.75). Mild A
cycl was observed in 14.5% (A
subj 13.9%), moderate A
cycl was observed in 3.2% (A
subj 3.2%), and severe A
cycl in 1.6% (A
subj 1.4%) of the subjects. The prevalence of anisometropia (A
cycl) in myopic subjects was 19.5% and in hyperopic subjects 18.0%, being slightly higher than the prevalence of A
subj in myopic (18.7%) and hyperopic (16.6%) subjects (
Figs. 1A,
1B). In summary, the trends and correlations between anisometropia and the analyzed variables were very similar for subjective and cycloplegic refraction with only minor differences.
First, the observed effect in 20- to 40-year-old hyperopes, with female sex being independently associated with A
subj, in logistic regression analysis did not reach statistical significance, when calculated for cycloplegic refraction (OR, 0.801; 95% CI' 0.516–1.244;
P = 0.323). Second, the correlation between increasing hyperopia (spherical ametropia) and decreasing anisometropia in the 20- to 40-year-old hyperopes (subjective refraction;
Table 2) was not verified by cycloplegic refraction recalculation (OR, 0.868,; 95% CI, 0.754–1.001;
P = 0.051). Third, in hyperopes age correlated negatively with A
cycl for subjects older than 60 years (compared with an age range of 50–59 years; OR, 0.289; 95% CI, 0.125–0.670,;
P = 0.004). For A
subj statistical significance was also evident in hyperopes ranging in age from 50 to 59 years (compared with the preceding decade). Fourth, in myopes the observed continuous increase in the OR with each decade of advancing age from the third to the fifth decades for A
subj was expanded to the sixth decade when calculated for cycloplegic refraction (>60 years compared with the preceding decade; OR, 1.903; 95% CI, 1.069–3.387;
P = 0.029).