ABSTRACT
PURPOSE: To investigate the incidence and characteristics of vertical deviation in the intermittent exotropia. METHODS: Fifty consecutive intermittent exotropes over age of 5 were prospectively studied. Patients with any significant ocular and neurologic abnormalities or orbital anatomic abnormalities, definite oblique dysfunction with A or V pattern were excluded. Ophthalmologic evaluation included visual acuity, ocular movements, measurements of angle of deviation by prism cover test, Bielschowsky head tilt test, stereoacuity test, and fundus observation for torsion by indirect ophthalmoscopy. RESULTS: We found that 27 children(54%) had concomitant hypertropia in primary position. Mean amount of hypertropia was 4.81 PD(range: 2~20 PD). Thirty nine children(78%) showed positive Bielschowsky head tilt test. No objective torsion was observed. No inferior oblique overaction was found except for only 2 patients. All subjects had good visual acuity and stereopsis. CONCLUSIONS: The incidence of vertical deviation in the intermittent exotropia is much higher than expected. All of the vertical deviations show positive Bielschowsky head tilt test.