Training in Gabor Orientation Identification Optimizes the Temporal Window of Adults With Anisometropic Amblyopia

We aimed to explore the mechanisms of perceptual learning (PL) in adults with anisometropic amblyopia.

Twelve amblyopic patients (mean age: 25.6 ± 1.04 years) and 12 normal participants (23.6 ± 0.43 years) were recruited. All participants were trained with a Gabor orientation identification task. Before and after training, visual acuity (VA) and the contrast thresholds in the task were measured under five different external noise conditions. The elaborated perceptual template model (ePTM) was adopted to probe learning mechanisms. Seven amblyopic participants (7/12) were retested three years after completion of training.

The amblyopic group exhibited enhanced VA and reduced contrast thresholds across all noise conditions, whereas the normal group showed a reduction in contrast threshold under one noise condition. ePTM analysis revealed that PL reduced internal additive noise by 8.72 ± 1.32 dB and 14.81 ± 0.66 dB and lowered the peak amplitude of the temporal window by 3.78 ± 0.74 dB and 1.35 ± 0.42 dB, in the amblyopic and normal groups, respectively. Interestingly, only the amblyopic group exhibited a significant sharpening of the temporal window (P = 0.033). Three-year follow-up showed that approximately 80% of VA improvement and 63% of the contrast-threshold reduction were retained.

PL significantly enhanced VA and reduced contrast thresholds in anisometropic amblyopia. Internal noise reduction contributed to the learning effects in both groups, and further temporal window optimization accounted for additional improvements in the amblyopic group. Performance improvements were largely maintained three years after training, supporting PL as a promising therapeutic approach for amblyopia.