The LANDMark study is an investigator-masked, prospective, longitudinal, controlled, natural history (observational) study conducted at two sites – Brisbane, Australia and Manchester, UK. The LANDMark study aims to: observe the natural history of diabetic neuropathy using novel non-invasive ophthalmic tests; prospectively characterise changes in corneal and retinal structural and functional (corneal subbasal nerve plexus, corneal sensation threshold, retinal thickness and retinal sensitivity) parameters in individuals with and without diabetic neuropathy; determine the predictive validity of the tests to measure these; and identify demographic and metabolic risk factors associated with these changes over time.