Perceptual Learning Based on Adaptive Contrast Detection Training for Intermittent Exotropia: A Pilot Double-Masked Randomized Controlled Study.

Purpose: This pilot randomized clinical study investigated the effects of individualized adaptive perceptual learning on control scores, stereopsis, and ocular alignment in children with intermittent exotropia (IXT). Methods: A total of 56 children with basic-type IXT (5-14 years old) were randomly assigned to either an experiment or placebo group, with 50 subjects included in the final analysis after excluding six participants due to poor adherence or incomplete follow-up. The experimental group underwent 30 days of individualized adaptive contrast detection training at their respective cutoff spatial frequencies, and the placebo group trained at a fixed low spatial frequency (3 cycles/degree). Primary outcome measures were control scores (near and distance). Secondary outcomes included stereoacuity (near and distance), ocular deviation magnitude (near and distance), and interocular suppression. Assessments were carried out before (e.g., baseline) and after (e.g., day 31) training and at follow-up visits (e.g., day 44 or 14 days after treatment cessation). Results: After training, both groups showed significant improvements in distance scores (experimental group, P < 0.001; placebo group, P = 0.001) and near control scores (experimental group, P = 0.005; placebo group, P = 0.003), albeit without significant difference between them (distance, P = 0.231; near, P = 0.738). The experimental group demonstrated greater enhancements in stereopsis (distance, P = 0.003; near, P = 0.006) and ocular deviation magnitude (distance: P = 0.043), as opposed to the placebo group. Improvements in control scores (near and distance), stereoacuity (near and distance), ocular deviation magnitude (near and distance), and interocular suppression were maintained in the experimental group at follow-up visits, whereas the placebo group regressed to baseline. Conclusions: Individualized adaptive perceptual learning at each individual's cutoff spatial frequency improved control abilities, stereopsis, and ocular alignment in children with IXT, with effects maintained (at least) 14 days after treatment cessation. The clinical significance of these findings requires further investigation.