An Arthroscope is essentially a long miniature lens system. It has a set of complex optics built in.
There are three main parts o this assembly:
1) Objective lens
2) Transmission system
3) Eyepiece
The objective lens is located at the tip of the arthroscope & is the first point of contact with the interior of the joint. Joints are tight spaces & in order to increase the field of view, prisms are used to bend the light so that the surgeon can easily look around the corners by simply rotating the lens, without having to physically move the arthroscope back & forth. Normally a 30 degree prism is used, but for more field of view 70 degree scopes are also available.
The transmission system consists of a series of rod shaped lenses within the shaft of the arthroscope, joined together by cement glue. They relay an inverted image of the object to the eyepiece. The rod lens system is known for its high light transmission efficiency compared to conventional lenses, because the air gaps between the lens is kept to a minimum.
The eyepiece serves to magnify & invert the inverted image relayed to it by the transmission system, thereby giving a natural view of the joint to the surgeon.
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