Citation: Li SZ-C, Yu W-Y, Choi K-Y, et al. Subclinical decrease in central inner retinal activity is associated with myopia development in children. Invest Ophthalmol Vis Sci. 2017;58:4399-4406. DOI:10.1167/ iovs.16-21279 PURPOSE. To investigate the characteristics of retinal electrophysiological activity in relation to early myopia development in children.METHODS. Fifty-six children aged 6 to 9 years with emmetropic refractive error (defined as ‡ À0.5 diopter [D] and þ0.5 D) were recruited. Cycloplegic refraction, axial length, and global flash multifocal electroretinogram (MOFO mfERG) at 49% and 96% contrast levels were recorded in all children at their first visit. The refraction and axial length measurements were repeated after 1 year. The amplitudes and implicit times of the direct component (DC) and the induced component (IC) of the MOFO mfERG obtained at the initial visit were analyzed. Correlations between the MOFO mfERG parameters and changes in refractive error and axial length were investigated. RESULTS.The mean spherical equivalent refractive error and axial length of the eyes of the children at the first visit were þ0.19 6 0.33 D and 23.14 6 0.6 mm, respectively. After 1 year, the mean refractive error increased by À0.55 6 0.53 D, whereas axial length increased by 0.37 6 0.22 mm. The changes in refractive error and axial length were significantly correlated with the central IC amplitudes at 49% contrast level measured at the initial visit (q ¼ 0.46, P < 0.001 and q ¼ À0.34, P ¼ 0.01, respectively).CONCLUSIONS. The prospective changes we have shown are believed to derive from central inner retina. These changes appear to precede myopia and could be a potential reference for juvenile myopia development.Keywords: myopia development, multifocal electroretinogram, children vision, inner retina E xcessive eyeball elongation causes myopia. In severe cases, it may result in retinal stretching, thinning, and changes in retinal cell morphology and pathology. Application of the ERG technique has provided ample evidence to confirm that myopia results in impaired retinal function. It has been reported that myopia in adults was associated with decreased nonlinear components of ERG responses, 1 multifocal ERG (mfERG) responses, 2,3 retinal adaptation response, 4 and inner retinal function. [5][6][7] Axial length was shown to be linearly related to ERG amplitudes, 8 first-order kernel, and the first slice of second-order kernel of mfERG responses. 9 The reduction in mfERG responses in myopic adults is believed to be due to the deterioration in retinal function associated with long-standing myopia. However, this explanation cannot be applied to myopic children, and discrepancies of ERG characteristics have been noted between myopic adults and children.2,7 Luu and his colleagues 2 conducted a cross-sectional study of mfERG measurement in 104 children and 31 adults with a range of refractive errors. They found a significant correlation between refractive error and mfERG response in adults, but this correlation ...