Transparent augmented-reality head-mounted displays vs medical-grade monitor in laryngologic endoscopy: A comparative FM-100 color discrimination and Fitts' law pointing study.

BACKGROUND

Endoscopic visualization systems are essential in contemporary otolaryngologic surgery. Although high-resolution surgical monitors provide excellent image quality, their size and fixed positioning may compromise ergonomic posture and limit the mobility of endoscopic systems.

OBJECTIVE

This study aimed to assess the applicability of transparent augmented-reality Head-Mounted Displays (HMDs) as an alternative or adjunct to conventional monitors, with particular emphasis on color fidelity (FM100) and psychomotor efficiency (Fitts' Law) in simulated endoscopic laryngologic surgery.

METHODS

Twenty otolaryngologists experienced in endoscopic sinus surgery evaluated endoscopic images using a standard 40-inch Full HD surgical monitor and two transparent HMDs (Epson Moverio BT-35/BT-40CS). Performance was assessed through a Fitts' Law test and the Farnsworth-Munsell color discrimination test. User feedback on comfort and usability was also collected. Data analysis was conducted using Linear Mixed-Effects Models (LMM), a statistical approach suitable for complex data structures.

RESULTS

Statistical analysis revealed a clear speed-accuracy trade-off and a significant performance deficit for HMDs. Both HMDs significantly impaired human color discrimination performance, resulting in a +51% to +60% increase in Total Error Score (TES) compared to the monitor. Furthermore, Fitts' Law modeling demonstrated that while the HMD HD device was faster at low task difficulty (18.9% faster movement time MT baseline), both HMDs were significantly more sensitive to task complexity. The monitor exhibited the most stable performance (MT increased by 6.3% per unit of Index of Difficulty ID), while HMDs showed increased costs (up to 16.4% increase in MT per unit of ID). Participants noted ergonomic improvements but reported limitations in visual alignment and device fit.

CONCLUSIONS

Head-mounted displays compromise the fidelity of color perception and lead to diminished efficiency stability under complex surgical task loads, limiting their current applicability for color-critical diagnostic procedures. However, their potential ergonomic advantages support their feasibility in mobile or resource-limited surgical environments where stable color fidelity is not paramount. Further evaluation focusing on improving HMD color accuracy and reducing visual demands is warranted.