What is the term for an optical aid used in visual examination that utilizes a lens train to bring the image to the eyepiece?

The term that describes an optical aid used in visual examination and employs a lens train to focus the image for observation through the eyepiece is "bore scope." A bore scope is specifically designed to allow users to inspect areas that are otherwise difficult to access, such as the interiors of engines, pipes, or other enclosed spaces. It typically consists of a set of lenses that magnify and focus the image, allowing for a clear view of the inspected area.

This design is essential for delivering a high-quality visual experience and is commonly used in various fields, including mechanical inspection, medical examination, and safety inspections. The lens train within the bore scope is crucial as it ensures that the image viewed through the eyepiece is properly illuminated and detailed, facilitating thorough inspections.

While other optical aids, like fiberoptic bore scopes, utilize fiber optics for illumination and can have similar applications, the fundamental term that describes the entire optical system with a lens train is the bore scope itself.