  Introduction. Macular degeneration (MD) causes central visual field loss.
When field defects occur in both eyes and overlap, parts of the visual pathways
are no longer stimulated. Previous reports have shown that this affects the
grey matter of the primary visual cortex, but possible effects on the preceding
visual pathway structures have not been fully established. Method. In this
multicentre study, we used high-resolution anatomical magnetic resonance
imaging and voxel-based morphometry to investigate the visual pathway
structures up to the primary visual cortex of patients with age-related macular
degeneration (AMD) and juvenile macular degeneration (JMD). Results. Compared
to age-matched healthy controls, in patients with JMD we found volumetric
reductions in the optic nerves, the chiasm, the lateral geniculate bodies, the
optic radiations and the visual cortex. In patients with AMD we found
volumetric reductions in the lateral geniculate bodies, the optic radiations
and the visual cortex. An unexpected finding was that AMD, but not JMD, was
associated with a reduction in frontal white matter volume. Conclusion. MD is
associated with degeneration of structures along the visual pathways. A
reduction in frontal white matter volume only present in the AMD patients may
constitute a neural correlate of previously reported association between AMD
and mild cognitive impairment.
  Keywords: macular degeneration - visual pathway - visual field - voxel-based
morphometry
