title: Newly designed ergonomic surgical binocular telescope with angulated optic axis.
abstract: OBJECTIVE
  Magnification by surgical loupes has the distinct merits of agility and nimbleness in observation, a wide stereo base effectuating superior depth sensation, and light augmentation by an objective lens that is larger than the pupil. However, continuous use of these loupes causes neck strain for surgeons as a result of flexion posture and fatigue. To minimize the strain and fatigue and maximize the advantages and performance of binocular telescopes, we have developed a novel optical design.
  
  
  METHODS
  To allow observation of the operative field with the surgeon's neck and eye in a straight position, the light path of the telescopes was angulated downward with roof prisms. For maximum image quality, Keplerian real-image optics were adopted.
  
  
  RESULTS
  The optics, finishing of the lens, and assembly were perfected through practical trials of more than 500 procedures over a period of 3 years.
  
  
  CONCLUSIONS
  The new ergonomically designed optics provide excellent image quality comparable to standing microscopes in the low to medium range of magnification, while effectively reducing the neck flexion of surgeons working in the operative field below and relieving the surgeon's fatigue during hours of continuous use.
authors: Department of Neurosurgery, Dokkyo University School of Medicine, Tochighi, Japan. kim@dokkyomed.ac.jp
authors: Phyo
authors: P
authors: Kim
authors: Masao
authors: M
authors: Joujiki
authors: Masao
authors: M
authors: Suzuki
authors: Keisuke
authors: K
authors: Ueki
authors: Yoshiaki
authors: Y
authors: Amano
mesh_terms: D004867:Equipment Design / Q000295:instrumentation / Q000592:standards / Q000639:trends; D006804:Ergonomics / Q000295:instrumentation* / Q000592:standards; D005139:Eyeglasses / Q000592:standards / Q000639:trends*; D006801:Humans; D007909:Lenses / Q000592:standards / Q000639:trends*; D009493:Neurosurgery / Q000295:instrumentation* / Q000592:standards; D055095:Optics and Photonics / Q000295:instrumentation*; D013525:Surgical Instruments / Q000592:standards / Q000639:trends; D015348:Vision, Binocular; D000078329:Workforce