Can occipital lesions produce pre-geniculate changes in humans?

Retrograde trans-synaptic degeneration (RTSD) has been well documented in animal studies: occipital lobectomies in adult primates leads to atrophy of not only the lateral geniculate nucleus, but also that of the optic nerves (ON). Clinical observations in humans, however, have varied in support of this concept. In one case, five decades after a cerebral vascular accident that resulted in a homonymous hemianiopia, the ON showed no evidence of atrophy. In contrast, a case series of patients with retro-geniculate lesions showed correlating ganglion cell layer (GCL) loss via spectral domain-optical coherence tomography (SD-OCT) in 68% of patients. Although this discrepancy may, in part, be explained by the availability of higher resolution imaging allowing characterization and quantification of neuronal loss in the anterior visual pathway that was previously missed, there may be other undetermined structural or functional changes in the posterior visual pathway that influence which injuries lead to RTSD.