A head-mounted operating binocular for augmented reality visualization in medicine--design and initial evaluation.

Area of Science:

• Medical Imaging
• Surgical Technology
• Computer-Aided Surgery

Background:

• Augmented reality (AR) offers promising applications in computer-aided surgery (CAS).
• Head-mounted displays (HMDs) are typically used for AR but face technical challenges limiting intraoperative use, including focal plane requirements and user acceptance.
• Existing HMDs present difficulties in aligning virtual graphics with the real surgical field and achieving user comfort.

Purpose of the Study:

• To adapt the Varioscope, a miniature head-mounted operating binocular, for AR applications in surgery.
• To evaluate the accuracy and clinical feasibility of the modified HMD for CAS.

Main Methods:

• The Varioscope HMD was modified for AR integration.
• Extensive laboratory study involving photogrammetric calibration of the HMD's displays to a real-world scene.
• 16 calibration trials were conducted with varying zoom factors and object distances.

Main Results:

• Mean calibration error was 1.24 +/- 0.38 pixels (0.12 +/- 0.05 mm) for a 640 x 480 display.
• Maximum error was 3.33 +/- 1.04 pixels (0.33 +/- 0.12 mm).
• Position measurement probe transformation to the display achieved sub-millimeter accuracy in 56% of cases, with errors below 2 mm in all cases.

Conclusions:

• The achieved accuracy of the modified Varioscope HMD is sufficient for various computer-aided surgery applications.
• This adaptation enhances the potential for clinical acceptance of AR in surgical environments.
• The study validates the Varioscope as a viable platform for AR-enhanced surgical procedures.