Endoscopy and biopsy of the orbit.

Flexible endoscopes produce high-quality images, are small in size, and can deliver microsurgical instruments or laser probes. Early attempts at orbital endoscopy were limited by the relatively large size and poor visualization of rigid endoscopes. We performed endoscopic orbital exploration using the Olympus HYF flexible endoscope in four live dog orbits. We achieved excellent visualization of orbital structures including the globe, blood vessels, extraocular muscles, intermuscular septa, optic nerve, and fat. Visualization, hemostasis, and dissection were aided by the use of hyaluronic acid infused through the endoscope. We biopsied fat and extraocular muscle without complication using Olympus endoscopic cup biopsy forceps (confirmed by histopathologic examination). Our experience indicates that orbital endoscopy aided by viscoelastic hydrodissection may permit a less invasive approach to optic nerve sheath fenestration, tumor biopsy and treatment, and the removal of foreign bodies.