Near esophoria is associated with high myopia

BACKGROUND: A retrospective study was undertaken to examine the hypothesis that esophoria is associated with higher amounts of myopia. METHODS: One hundred and forty-four subjects were selected from the files of optometry clinics at the Department of Optometry, National University of Malaysia, from the years 1995 to 1998 inclusive. These subjects were matched in terms of age group, sex, race and near phoria group. Near phorias were determined by Maddox wing technique and were classified into three groups: more than six prism dioptres exophoria, zero to six prism dioptres exophoria and any esophorias. RESULTS: One way analysis of variance revealed that there were significant differences in mean myopias between the three phoria groups (ANOVA, F(2,141) = 5.34, p < 0.01). Further analysis with the Student-Newman-Keuls test showed that the amount of myopia is significantly higher in the esophoric group than in the other two groups. CONCLUSIONS: The results support the hypothesis that near esophoria is associated with high myopia. This study suggests that near phoria might be an important factor in myopia development.