Trans-synaptic Retrograde Degeneration Following Hemispherectomy in Childhood.

Trans-synaptic retrograde degeneration (TRD) in the human visual system has been established. However there are few studies demonstrating macular thinning of the Retinal Ganglion cell Layer and/or Inner Plexiform layer (RGCL-IPL), corresponding to an acquired homonymous hemianopia. We report a 17 year old with a homonymous hemianopia, secondary to a hemispherectomy for intractable epilepsy. Three years following hemispherectomy, Optical Coherence Tomography (OCT) revealed evidence of TRD, corresponding to his complete homonymous hemianopia. Macular maps of the RGCL-IPL thickness provides useful additional information to measurements of optic nerve Retinal Nerve Fibre Layer Thickness (RNFL) in identifying TRD in acquired homonymous hemianopia.