Dissociated vertical deviation in patients with intermittent exotropia

Objective:To describe the characteristics of dissociated vertical deviation(DVD) in pa-tients with intermittent exotropia and determine whether the age of strabismus onset and the degree of stere-opsis are related to the development of DVD in patients with intermittent exotropia and DVD.Methods:177 patients were retrospectively recorded and divided into three groups:(1) intermittent exotropia with DVD;(2) intermittent exotropia without DVD and(3) simple DVD.Age of strabismus onset,binocular vision function,and vertical deviation measurements were analyzed.Results:39 patients with intermittent ex-otropia and DVD were identified.In intermittent exotropia with DVD and intermittent exotropia without DVD group,the mean age of strabismus onset was 45.0 months and 82.9 months,respectively(P0.01).Group 1 showed worse binocular visual function than group 2(P0.01).The measurements of vertical devia-tion in group1 and 3 were 14.5△±9.6△ and 23.7△±15.4△,respectively(P0.05).Conclusion:Intermittent exotropia with DVD is characterized by earlier onset of strabismus and worse stereopsis,which suggest that poor binocular visual function in early period of life may be related to the development of DVD.Horizontal deviation in DVD patients with intermittent exotropia may have effect on the size of vertical deviation.