Effect of motion stimulation without changing binocular disparity on stereopsis in strabismus patients.

PURPOSE

To evaluate the effect of motion stimulation without changing binocular disparity on stereopsis in strabismic patients.

METHODS

Static and moving stereopsis were measured in 120 normal children and 30 strabismic patients (9 esotropia, 14 exotropia, 7 intermittent exotropia). Using a portable game device (PSP; SONY, Japan), we created stereoscopic targets and produced stereopsis using a closed tube binocular viewing device. Stereoscopic disparity of targets was adjusted in 20 steps of 100 s each over a range from 2000 s to 100 s. In stereo testing using our apparatus, static test targets were used for static stereograms (SS), and test targets with clockwise planar rotation were used for moving stereograms (MS) without changing binocular disparity.

RESULTS

All normal children were able to perceive stereopsis with stereoscopic disparity from 2000 s to 100 s, and were interested in our apparatus, more than the Titmus stereo tests. All esotropic patients failed both SS and MS. In the exotropic patients (14 exotropia and 17 intermittent exotropia patients), 19 (90.4%) passed the MS, and 13 (61.9%) passed the SS.

CONCLUSION

The exotropic patient might be able to perceive the binocular stereopsis by moving stereogram that was created by adding clockwise planner rotation without changing the binocular disparity to the static stereopsis target.