A comparative study of the optical characteristics of commonly used sinoscopes: do you know where you are looking?
Endoscopic ethmoidectomy is a delicate operation on the thin, honey-comb-like laminae of the ethmoidal sinuses. A high degree of precision is required to minimize disruption of the natural sinus mucociliary clearance system and to reduce the risk of orbital and skull base complications. It is therefore important that surgeons are aware of variation in the optical characteristics of the rod-lens telescopes produced by different manufacturers. A simple but precision endoscope goniometer was designed and manufactured. This was used to carry out a comparative study of the sinus telescopes in common use. The results showed significant variation in the view angle of the four brands of telescopes (Karl Storz, Olympus, Richards Smith & Nephew, and Richard Wolf) tested. Differences in the position of the horizon in the visual field, and different degrees of visuospatial distortion were evident. We also noted and measured the blind angle of telescopes, which, by virtue of a high degree of angulation, cannot view the horizon.