Study On The Stereopsis Of Intermittent And Constant Exotropia

Intermittent and constant exotropia are two main kinds of exotropia of acquired comitant exotropia. In the past, the study on their stereopsis was respective or combined, in spite of some constant exotropia may represent decompensated intermittent exotropia. This study establish the diagnostic criteria of constant exotropia which had an intermittent period and demonstrate the diagnostic criteria by the contrast of 2 kinds of constant exotropia. Then to investigate the postoperative stereopsis recovery of intermittent exotropia and constant exotropia which had an intermittent period , the influence to the postoperative sensory outcome of surgical age and Duration of strabismus and the fit time of strabismus surgery. YAN Shao-ming's stereogram and synoptophore were tested and analysed before and 2 weeks, 4 weeks, 12 weeks after surgery.By studying postoperative sensory outcome of the 48 intermittent exotropia and constant exotropia which had an intermittent period, this study find: (1) Preoperative distant stereopsis is deterioration more severely than near stereopsis .The recovery of postoperative stereopsis is from near to far distance. Recovery of distant stereopsis usually needs more time. (2) Patients of 4~7 years old group recover better than those of the other two groups in both near and distant stereopsis. They have a significantly greater chance of having normal postoperative stereopsis. (3) Patients with strabismus duration 5 years or less have a better postoperative stereopsis than those with strabismus duration 5 years more. (4) Conversely, patients with superior postoperative sensory outcome have an early surgery and a shorter duration of strabismus. Therefore, surgery should be performed for a better recovery of stereopsis before age 7, less than 5 years of strabismus duration.