[Development of dynamic stereopsis after eye muscle operations for binocular vision impairment].
BACKGROUND: Strabism usually impairs central stereopsis irreversibly after a short time duration,however, the retinal periphery is more resistant to deterioration by binocular impairment. METHODS: In this prospective study 46 strabismic patients (9-56 years old) were tested for dynamic stereopsis in the peripheral visual field up to 20 degrees eccentricity. The effect of realignment of the visual axes by surgery on dynamic stereopsis was tested before and after surgery in 40 out of these patients. Patients were tested qualitatively for dynamically stereoactive fields of vision and quantitatively for the threshold value needed to create a three-dimensional impression. RESULT: We found residual dynamic stereopsis in 30% of patients without central static stereopsis: 56% of the patients improved after surgery, either through a significant (p<0.01) gain of stereoactive fields or through a decrease of threshold values. CONCLUSION: Strabismus surgery has benefits for the patients outside classical tests and seems to be independent of the static depth perception.