Perceptual Learning Versus Part-Time Patching for Deprivation Amblyopia in Limbal Dermoid Children after Keratoplasty: A Randomized Controlled Trial

Background: To evaluate the contrast sensitivity function(CSF) for children with limbal dermoid(LD) after keratoplasty, then compare the therapeutic efficacy of perceptual learning(PL) versus part-time patching on improving CSF and visual acuity(VA).Methods: This study included two stages: a prospective cross-sectional study and a randomised controlled trial(RCT). Twenty-five limbal dermoid children comprised the LD group, and 25 normal children comprised the normal group, which were divided into the optical defocusing group who wore an optical defocus to simulate monocular blurred VA and normal viewing group. The LD group was further randomly allocated into two arms: 9 underwent PL combined patching, and 8 underwent only patching. The primary outcomes was the area under log CSF(AULCSF) of CSF, and secondary outcome was BCVA . This study is registered as NCT03447041.Results: In the stage I, the area under log CSF(AULCSF) and the cutoff spatial frequency in the CSF were obviously reduced in the LD group compared with the optical defocus and normal viewing group. In the stage II, the primary outcome, the between-group difference in changes of AULCSF’s improvement between PL and patching group from the baseline to the 6 th month was 0.59(95%CI: 0.32, 0.86, p<0.001), and the between-group difference in changes of visual improvement from the baseline to the 6th month was -0.30(95%CI: -0.46, -0.14, p<0.001).Conclusion: Children suffering from limbal dermoid with amblyopia exhibited CSF deficits as well as VA loss simultaneously. PL could improve CSF and VA in the amblyopic eye better than patching.Clinical Trial Registration Details: The trial was registered at clinicaltrials.gov (PRS, ID NCT03447041). Funding Information: This work was supported by the Key-Area Research and Development Program of Guangdong Province(No· 2019B010152001), and Guangzhou Science and Technology Program(No·202103000043).Declaration of Interests: We declare no conflicts of interests.Ethics Approval Statement: The research was performed according to the tenets of the Declaration of Helsinki. The trial protocol and consent form were reviewed and approved by the Zhongshan Ophthalmic Ethical Committee. Clinical measurements were performed after written informed consent had been obtained from all participants.