Ocular Imaging and Electrophysiology

This article describes how ocular imaging techniques and electrophysiology studies aid in the localization, diagnosis, and management of disorders affecting vision.

The retina and optic nerve are functionally and embryologically part of the central nervous system, and they are the exceptional parts of the brain that can be directly examined by the neurologist or ophthalmologist (through the fundus examination). Ocular imaging techniques including fundus photography, optical coherence tomography (OCT), retinal angiography, and orbital ultrasound allow more detailed assessments of the retina and optic nerve. In some settings, nonmydriatic fundus photography can provide more accurate assessments than direct ophthalmoscopy. OCT allows high-resolution imaging of retinal and optic nerve structures. Combined with automated segmentation algorithms to allow for the measurement of retinal nerve fiber layer and macular ganglion cell layer thicknesses, clinicians and investigators can determine how these layers are affected in optic neuropathies and some neurodegenerative disorders. Electrophysiologic studies provide complementary information to ocular imaging modalities. Electroretinography assesses the function primarily of photoreceptor rods and cones, whereas visual evoked potentials assess primarily optic nerve function.

Ocular imaging and electrophysiology techniques aid in diagnosing and managing neuro-ophthalmic disorders and are increasingly accessible to neurologists.