Stereo distance in XT
Reviewed by Fiona Rowe

The test distance effect on stereoacuity was explored in a population with intermittent exotropia along with use of two types of stereograms with crossed and uncrossed disparity. At near and distance distances, the median for both disparities was 60”; 79% showed no difference in thresholds for stereoacuity at either distance for crossed disparity. For uncrossed disparity, distance stereoacuity was significantly worse than near stereoacuity. Near stereoacuity was significantly better with crossed than uncrossed disparity. Age, angle of deviation at near and distance fixation ad physiological diplopia did not influence stereoacuity. The authors suggest that specific cases of intermittent exotropia showing differences in near / distance stereoacuity may have poorer control of eye position. 

Influence of test distance on stereoacuity in intermittent exotropia.
Seki Y, Wakayama A, Takahashi R, et al.
STRABISMUS
2017;25(1):12-6.