Abstract
Abstract: :
Purpose: To search for a relationship between the lateral heterophoria of mothers and that of their myopic children. Previous studies have shown that there is a convergent shift in the near phoria at the time of myopia onset in children and that a high AC/A ratio is a risk factor for myopia development. Parental myopia is a risk factor for myopia development in their children. Methods: Thirty myopic children and their birth mothers were examined. Age of the children ranged from 7 to 17; and age of the mothers ranged from 30 to 48 years. Phoria was measured with the vonGraefe technique at 6 m and 40 cm through the distance correction in a phoropter. Refractive error was estimated by neutralization of correction; or subjective refraction, if the correction was prescribed more than 1 yr ago. Exophoria was coded as negative; all values are in prism diopters. Pearson correlation coefficients between the following pairs of variables were calculated: between the phorias of mothers and their children, between phorias at 6 m and at 40 cm, and between refractive errors of mothers and their children. Results: Phoria at 4 m averaged -0.01 (SE 3.24) for children and 0.13 (2.76) for mothers; at 40 cm 1.81 (7.07) for children and -2.33 (5.09) for mothers. We found no evidence of an association between a child's heterophoria and that of their mothers (r = 0.037 for 6 m; r = - 0.086 for 40 cm). The refractive error of the mothers and their children was weakly correlated (r = 0.360, p = 0.051). The vonGraefe phoria at 6 m was strongly correlated with that at 40 cm (for mothers r = 0.763, p = 0.001; for children r = 0.676, p = 0.001). Conclusion: There was no simple relationship between lateral phorias of mothers and their children at either test distance. The phoria value at 6 m was correlated with the phoria value at the 40 cm test distance for both mothers and their chidren.
Keywords: 329 binocular vision/stereopsis • 481 myopia • 623 visual development: infancy and childhood