AIM:To study the differences of accommodative responses between the two eyes under 3 different polarized viewing conditions.

METHODS:Fifteen volunteers with emmetrope were recruited into this study(aged 18～38), 6 males and 9 females. Three different viewing conditions were set up by using polarizing glasses and liquid crystal display:(1)right eye could see the visual target on the screen, but left eye cannot see it;(2)left eye could see the visual target on the screen, but right eye cannot see it;(3)both eyes could see the target. Accommodative responses were measured by infrared auto-refractor when fixating at the target at 5, 2, 1, 0.5 and 0.33m under the above 3 viewing conditions. The differences of accommodative responses under different viewing conditions were compared by using variance analysis of repeated measuring and t test.

RESULTS:Significant differences of accommodative responses between the two eyes were found under condition(1)and(2)at all the fixating distance. The accommodative responses in used eyes which can see the visual target were higher than in non-used eyes which cannot see the visual target(P<0.05). No differences of accommodative responses were found under condition(3)at all distance(P>0.05).

CONCLUSION:Ciliary muscles in the used eyes were more relatively tonic than non-used eyes under binocular open viewing condition. The imbalance of accommodative responses between two eyes may be one of the risk factors resulting into the occurrence of myopia.