Optical coherence tomography in the investigation of systemic neurologic disease.

Optical coherence tomography (OCT) is a well-established technique for the clinical examination, diagnosis, severity staging and monitoring of ophthalmic disorders. The application of this technology has more recently been extended beyond ophthalmic disease, whereby it has been demonstrated that OCT can serve as an ophthalmic marker for a range of systemic neurodegenerative disorders, such as Parkinson's disease, multiple sclerosis, Alzheimer's disease and diabetic peripheral neuropathy. This review will focus on the clinical utility of OCT-derived retinal measures for the investigation of these conditions.