Detection of abnormal visual cortex in children with amblyopia by voxel-based morphometry.

PURPOSE To detect the abnormalities of gray matter in children with amblyopia by voxel-based morphometry (VBM). DESIGN Prospective, nonrandomized clinical trial. METHODS Thirteen children with amblyopia and 14 normally sighted children underwent magnetic resonance (MR) examination. The two groups were age-matched with a mean age of 5.8 years. In the amblyopia group, five children had strabismus amblyopia, and eight had anisometropic amblyopia. We analyzed the original 3-dimensional T1 brain images using the VBM module within the widely used analysis software package SPM2 (Welcome Department of Cognitive Neurology, London, United Kingdom). After normalization, segmentation, and smoothing of the images, comparison between amblyopic and control groups was derived for the gray matter of the entire brain using parametric statistics. RESULTS The results of VBM analysis indicated that the amblyopic group had decreased gray matter density in the middle frontal gyrus, parahippocampal gyrus, fusiform gyrus, inferior temporal gyrus of the left hemisphere, and the bilateral calcarine cortices. The radii of these regions ranged from 12 to 36 voxels. These abnormalities were consistent with morphologic changes in brain regions related to visual function. CONCLUSIONS Using MR and VBM analysis, we detected morphologic changes in the visual cortex of children with amblyopia, which may indicate developmental abnormalities of visual cortex during the critical growth period.