Optical coherence tomography-based cochlear endoscopy through the human round window membrane.

The human cochlea, which encapsulates the hearing organ, remains difficult to image using current medical tools due to its delicate structure and location behind dense bone. Optical coherence tomography (OCT) has become an essential technology for imaging cochlear morphology and function in animal models, offering high spatial and temporal resolution. Our previous work demonstrated OCT's ability to image cochlear structures in mouse models and to measure sound-induced vibrations at a nanometer scale. Translating this approach to human patients, however, requires overcoming challenges such as accessing the cochlea non-invasively through the ear canal. We previously designed a hand-held OCT endoscope for this purpose, but the initial design and lack of a camera made it very difficult to use in a clinical setting. In this paper, we present a redesigned OCT endoscope to image the human cochlea that addresses these limitations by reducing its size, improving visibility, and incorporating a forward-looking fiber bundle and camera for better navigation. We validated the device using both an opal checkerboard target and a cadaver temporal bone, demonstrating the ability to navigate to the round window niche via the ear canal. These advancements allow for detailed, real-time imaging of cochlear structures and represent a step toward the clinical application of OCT for diagnosing and treating hearing disorders of the inner ear.