Stereotaxic endoscopy for the ocular imaging of awake, freely moving animal models

Stereotaxic instruments are increasingly used in research animals for the study of disease, but typically require restraints and anesthetic procedures. A stereotaxic head mount that enables imaging of the anterior chamber of the eye in alert and freely mobile mice is presented in this study. The head mount is fitted based on computed tomography scans and manufactured using 3D printing. The system is placed noninvasively using temporal mount bars and a snout mount, without breaking the skin or risking suffocation, while an instrument channel stabilizes the ocular probes. With a flexible micro-endoscopic probe and a confocal scanning laser microscopy system, <20 μm resolution is achieved in vivo with a field of view of nearly 1 mm. Discomfort is minimal, and further adaptations for minimally invasive neuroscience, optogenetics and auditory studies are possible.