Macular ganglion-cell-complex layer thinning and optic nerve integrity in drug-naïve Parkinson's disease

To reveal the macular inner retinal change linked to axonal degeneration in Parkinson's disease (PD), we performed macular optical coherence tomography scan and diffusion tensor imaging of the retrobulbar optic nerve on both eyes of 36 drug-naïve PD patients. Thicknesses of inner retinal layers were automatically measured, and correlation analysis was conducted between the retinal thickness and diffusion parameters of the optic nerve. PD patients showed thinning of the inner retinal layers compared to control data. Thicknesses of the ganglion cell and inner plexiform layers were both correlated positively with fractional anisotropy and negatively with diffusivity indices of ipsilateral optic nerve (FDR-adjusted p < 0.05). This study revealed a novel in vivo connection between macular parafoveal ganglion cell change and integrity in the retrobulbar optic nerve in drug-naïve PD.