Diffusion tensor imaging reveals normal geniculocalcarine-tract integrity in acquired blindness

We investigated optic nerve and geniculocalcarine tract (GCT) in acquired blindness (AB) using routine cranium magnetic resonance imaging and diffusion tensor imaging. Twenty individuals with AB were compared with 20 normally sighted (NS) individuals. The transverse diameters of optic nerves in NS were significantly bigger than the AB participants in T1WI maps. AB participants had higher mean diffusivity and transverse diffusivity and lower fractional anisotropy and primary diffusivity in the optic nerve. This pattern of diffusion change suggests axonal degeneration or atrophy of nerve fibers. No diffusion-index alterations in the GCT were found between AB participants and NS controls. White matter integrity remained normal in the GCT. Thus, the GCT may not rely on visual afferent input to maintain integrity after development.

► Investigate acquired blindness' optic nerve and GCT using conventional MRI and DTI.
► The optic nerves were atrophied in blindness.
► No diffusion indices alterations of GCT were found in blindness.
► GCT may do not rely on optic afferent input to maintain integrity after development.