tokens: Methods Patients with genetically confirmed CMT2A ( n = 5 ) , CMT1A ( n = 9 ) and CMTX1 ( n = 10 ) underwent high- and low - contrast acuity testing using Sloan letter charts , and circumpapillary retinal nerve fiber layer ( RNFL ) and macular total retinal , RNFL , and ganglion cell layer / inner plexiform layer thickness was measured using spectral domain optical coherence tomography ( OCT ) .