Dynamic Stereopsis Is Abnormal in Treated Anisometropic Amblyopia

The purpose of this study was to assess the dynamic stereoscopic function in treated anisometropic amblyopes with restored visual acuity.

Twelve treated anisometropic amblyopes (best-corrected visual acuity [BCVA] ≤ 0.1 logMAR), 8 non-amblyopic anisometropes, and 12 age-matched emmetropes with normal vision (BCVA ≤ 0.0 logMAR) participated in this experiment. Stimuli comprised 50 randomly positioned, limited-lifetime Gabor elements with lateral motion (0.17 degrees/s to 5.33 degrees/s): half of the elements moving in one direction were presented at the fixation plane and the other half moving in the opposite direction were presented at an uncrossed disparity relative to the fixation plane. Motion directions were counterbalanced across planes, and dynamic stereo performance was quantified using a staircase method.

For the range of motion speeds we tested, we observed clear speed tuning of the stereo sensitivity for all three groups (Remmetropia = 0.93, Ranisometropia = 0.97, and Rtreated-amblyopia = 0.75). Treated amblyopes showed significantly reduced dynamic stereo sensitivity (P = 0.007) compared to that of other two groups, although speed-tuning shapes did not differ. Dynamic stereopsis sensitivity was uncorrelated with anisometropia degree or static stereopsis.

Even with restored visual acuity, treated amblyopes continues to exhibit binocular deficits, quantified here in terms of dynamic stereopsis. This highlights the need for therapies specifically designed to restore binocular visual function for a comprehensive cure.