Multimodal imaging in neuro-ophthalmology

Multimodal imaging has become a vital pillar in modern ophthalmology. Initially this was restricted to retinal diagnostics but now this approach is central even to neuro-ophthalmology, where the retina and optic nerve offer an accessible window to the central nervous system. Multimodal refers to the strategic combination of diverse imaging tools to gather complementary structural, functional, and vascular information, ultimately improving diagnostic precision. In Neuro-Ophthalmology, we draw upon a wide spectrum of multimodal imaging techniques, spanning both ocular and non-ocular investigations. Ocular imaging can be broadly categorized into non-invasive and invasive modalities. Non-invasive modalities include fundus photography, scanning laser ophthalmoscopy, fundus autofluorescence, laser speckle flowgraphy, Humphrey field analyzer, electrophysiological tests, ocular ultrasonography, optical coherence tomography (OCT), and OCT angiography. Invasive imaging involves fundus fluorescein angiography and indocyanine green angiography. Non-ocular imaging encompasses Doppler studies, computerized tomography (CT) scans, CT angiography, magnetic resonance imaging (MRI) with venography or angiography and digital subtraction angiography. Each is presented through a common framework of principle, clinical use, comparative utility, and limitations, followed by a practical, syndrome-based scheme for selecting tests and escalating to neuroimaging when red flags arise. With these technological advances, we now have access to an extensive arsenal of ocular and non-ocular modalities that complement each other to refine diagnosis and management. However, when not used judiciously, these tools can be unnecessary and cost-inefficient. Therefore, understanding which test is most appropriate in a given clinical scenario is crucial for maximizing their value.