Ocular Dominance, Refraction and Axial Length in Australian Twins

Abstract

Purpose: : To investigate the association of ocular dominance with refraction and axial length in Australian twins.

Methods: : Australian twins were examined as part of the Twins Eye Study in Tasmania (TEST) and Brisbane Adolescent Twin Study (BATS). Twin participants completed a questionnaire on their past medical and ocular history, followed by a comprehensive ocular examination. Ocular dominance was assessed by the Miles Test, a method whereby the participant brings both hands together at arms length to create a small opening, through which a distance object is viewed.

Results: : A total of 1867 twin participants aged between 5 and 90years had ocular dominance recorded. Mean ages of the twin participants were 21.2 years(SD=12.5) with 43.9% males and 56.1% females. There was no statistically significant difference in the spherical equivalent (SEQ) of the dominant eye -0.25D(SD=1.48D) and non dominant eye -0.23D(SD=1.62D) (p=0.098). There was a difference in mean astigmatism between dominant -0.36D(SD=0.44) and non dominant eyes -0.40D(SD=0.51) (p<0.001). The mean axial length of the dominant eye was 23.20mm(SD=0.89) compared to 23.18 mm(SD=0.9) in the non-dominant eye and this was statistically significant (p=0.012).

Conclusions: : Ocular dominance is clinically relevant for monovision correction in contact lens wear/ refractive or cataract surgery as well as a determinant of visual handicap when the dominant eye is affected with disease. Consideration of ocular parameters associated with eye dominance should be factored into genetic studies of dominance.

Keywords: refractive error development • myopia • clinical (human) or epidemiologic studies: risk factor assessment