Yongqing Guan1, Liqun Ren2

Purpose: To investigate the possible mechanism of intermittent exotropia.

Method: Measured the fusion range of the object, converged fusion and diverged fusion, as well as near and distant stereoscopy.

Results: There was no statistical significance in diverged fusion between the intermittent exotropia group and the normal control group (P > 0.05). The converged fusion in the intermittent exotropia group was significantly smaller than that of the normal control group (P < 0.01).The distant horizontal diverged fusion in the intermittent exotropia group was significantly larger than that of the normal control group. The difference showed statistical significance between the two groups (P < 0.01).The distant horizontal converged fusion in the intermittent exotropia group was significantly lower than that of the normal control group. The difference showed statistical significance between the two groups (P < 0.01).The distant stereopsis in the intermittent exotropia group was significantly lower than that of the control group. The difference showed statistical significance between the two groups (P < 0.01). Conclusion: (1) Discrete fusion of hyperfunction may be one of the mechanisms of intermittent exotropia. (2) The stereoscopic visual impairment of intermittent exotropia might firstly occur in the distant stereoscopic vision.