Fig. 2

A simplified schematic diagram of an ophthalmic fiberoptic microendoscope. An objective lens system mounted at the distal (intraocular) end of an endoscope’s intraocular probe forms a high-resolution ophthalmoscopic image on the end-surface of a coherent fiberoptic bundle (image guide). The image guide relays this image to its proximal end, which is interfaced with a video camera. The camera transmits the video data to a high-resolution computer monitor. Optical fibers for illumination and laser photocoagulation extend from their central console interfaces through a handpiece to the distal end of the intraocular probe. A fiberoptic bundle is classified as coherent if the optical fibers in the bundle have same position relative to each other at the beginning and end of the bundle. Coherent bundles can serve as image guides, preserving the information in transmitted optical images. Gradient index and Hopkins rod lens microendoscopes replace fiberoptic image guides with higher resolution lens-based, image-relay systems