den Haan J, et al. - In this investigation, researchers assessed retinal (layer) thickness as non-invasive biomarker of neurodegeneration in well-characterized candidates with posterior cortical atrophy (PCA) and typical Alzheimer’s disease (tAD). Participants in the study were 48 patients, 25 patients with PCA and 23 with tAD, in addition to 70 cognitively healthy controls. Despite unequivocal differences on standard clinical, neuro-imaging and cerebrospinal fluid measures, retinal thickness did not discriminate between tAD and PCA from controls or from one another. Findings do not support the usefulness of optical coherence tomography as an AD biomarker for cross-sectional retinal thickness measurements and underline the need for strict clinical and scientific validation research. Future studies on a molecular level such as amyloid and tau should also focus on more specific AD retinal biomarkers.