Cystoscope Speculum

It is the optical part of the cystoscope, which is composed of multiple magnifiers such as the objective lens, the intermediate mirror, the eyepiece and the prism.
The objective lens is a flat convex lens. The magnification of the lens and the diameter of the speculum are the key factors determining the size of the internal field of view. If the magnification of the speculum and the diameter of the speculum both increase, the internal field of view must also increase.
Intermediate mirror early direct mirror, the structure is simple, only one intermediate mirror, the light reflected by the object needs to go through a long pipe diameter to reach the intermediate mirror, most of the light is absorbed by the tube wall, so that the object is blurred. In order to improve the shortcomings, the modern cystoscope has been composed of most of the double lifting lenses (between the objective lens and the intermediate mirror), so that the loss of light to a minimum, and the production of attention to correct the color difference, and strive to achieve the objective of realistic image and color as usual.
The eyepiece is also a flat convex lens, so that after the object passes through the above sets of lenses, a reduced and upright image is formed in front of the eyepiece. A lens must be installed at the eyepiece for proper magnification to make the image clearer. The magnification of the lens is closely related to the loss of light. The larger the magnification, the more obvious the loss of light, generally 10-20 times magnification is appropriate. Each type of cystoscope has its own magnification.
Prism Prism is used for speculum, which fundamentally changes the shortcomings of direct cystoscope with large blind area and small field of view. The prism used in the mirror is a right Angle prism, the right Angle of the two short face, one side is connected with the objective lens, the other side is perpendicular to the mirror axis. The image enters the speculum from a short edge and refracts at a 90 degree Angle through a long oblique edge. Through the middle mirror, the eye piece is projected into the field of vision, but the object image seen is inverted and the original object is reversed. Due to the continuous improvement of modern optical technology, all kinds of cystoscopes used in clinical use have an Amici prism in front of the eyepiece.
In order to eliminate the blind area during cystoscopy to the greatest extent, so as to fully and correctly peer into the interior of the bladder, many authors have continuously improved on the basis of the direct original speculum, and have designed and made a variety of speculum with different reflection angles, such as 90 degrees of the front speculum, 115 degrees of the front mirror, and 25 degrees of the reverse mirror. The surgeon can choose the speculum with appropriate reflection Angle according to the need of examination