Extending Treatment Duration in Perceptual Learning for Amblyopia.

Purpose: Perceptual learning (PL) is a novel therapeutic approach for the treatment of amblyopia. This study evaluated whether extending the duration of PL could yield sustained therapeutic benefits in amblyopia management. Design: A retrospective observational design. Methods: Analysis included 93 of 100 patients who completed 6-month lateral masking PL and had 3- or 6-month follow-up data. Missing data were handled using multiple imputation by chained equations. Longitudinal changes in visual function-including best-corrected visual acuity (BCVA), contrast sensitivity function (CSF), and stereopsis-were evaluated using a linear mixed-effects model. To identify factors associated with improvements in BCVA and area under the log CSF (AULCSF), multivariable linear regression models were constructed, incorporating all relevant covariates selected based on clinical significance and evidence from existing literature. Only 1 amblyopic eye per patient was included in the analysis of BCVA and AULCSF. In cases of bilateral amblyopia, the worse eye was selected for the primary analysis. Sensitivity analyses were conducted in 2 ways: (1) using measurements from the better eye and (2) using datasets in which missing values had been imputed based on logical rules; the missing value was replaced with the worse outcome of the 2 observed values from the remaining time points. Main Outcome Measures: Measurements included BCVA, CSF, and stereoacuity. Results: A total of 93 participants (46 males and 47 females) were enrolled, with a mean age of 15.3 ± 8.3 years. Amblyopia subtypes included: isoametropic (n = 8), anisometropic (n = 63), strabismic (n = 12), deprivation (n = 1), and mixed (n = 9). Analysis revealed significant and sustained improvements in both BCVA and the AULCSF. Near stereopsis also improved following 3 months of PL training. However, further extension of the training duration did not result in additional significant gains in stereopsis. Multivariable linear regression analysis indicated that initial baseline visual function and history of occlusion therapy were the primary factors associated with the improvement of BCVA and AULCSF. Conclusions: Perceptual learning treatment can improve the visual function of amblyopia patients. Considering that extending the duration of PL still resulted in measurable visual improvements, a 6-month training of PL appears to be necessary. Financial Disclosures: The authors have no proprietary or commercial interest in any materials discussed in this article.