Visual fatigue while watching 3D stimuli from different positions

3D Da Vinci robotic surgery: is it a risk to the surgeon's eye health?

Da Vinci three-dimensional (3D) system has been increasingly used in customary surgical settings, gaining fundamental relevance for abdominal, urological, and gynecological laparoscopic surgery. The aim of this research is to evaluate the degree of discomfort and potential changes in the binocular vision and ocular motility of surgical operators, who employ 3D vision systems during Da Vinci robotic surgery. Twenty-four surgeons were enrolled in the study, including twelve who typically use the 3D Da Vinci system and twelve who routinely employ 2D system. Routine general ophthalmological and orthoptic examinations were conducted at baseline (T0), the day before surgery, and 30 min after the 3D or 2D surgery (T1). In addition, surgeons were interviewed using a questionnaire of 18 symptoms, with each item containing three questions regarding the frequency, severity, and bothersomeness of the symptoms, in order to evaluate the degree of discomfort. Mean age at evaluation was 45.28 ± 8.71 years (range 33-63 years). Cover test, uncover test, and fusional amplitude showed no statistically significant difference. After surgery, no statistical difference was observed in the Da Vinci group on the TNO stereotest (p > 0.9999). However, the difference in the 2D group resulted statistically significant (p = 0.0156). Comparing participants (p 0.0001) and time (T0-T1; p = 0.0137), the difference between the two groups was statistically significant. Surgeons using 2D systems reported more discomfort than those using 3D systems. The absence of short-term consequences following surgery with the Da Vinci 3D system is a promising conclusion, considering the numerous advantages of this technology. Nonetheless, multicenter investigations and more studies are required to verify and interpret our findings.

Motion and viewing analysis during minimally invasive surgery for autostereoscopic visualization

PURPOSE

Autostereoscopic 3D visualization (ASV) forms a potentially appealing alternative to stereoscopic 3D displays to help surgeons regain depth perception during minimally invasive surgery (MIS). However, the feasibility of using single-viewer ASV has not yet been demonstrated in a clinical context. The purpose of the study is to analyze the current surgical workflow and display usage and assess the potential for using ASV in MIS applications. Additionally, the study seeks to acquire a better understanding of key design requirements, such as the eye-tracking performance and the lenticular lens 3D workspace.

METHODS

Two types of gynecologic interventions were investigated. A vision-based tracking system was developed, consisting of depth cameras mounted on the displays and ArUco markers placed on the hair caps of clinicians and the wall of the operating room. This allowed simultaneous tracking of the pose of operating staff and displays.

RESULTS

Overall 20 surgeries were recorded, where 4 clinicians operated using 3 displays. Users were typically standing at a mean distance of 1900 mm in a range from to 1200 to 2300 mm from the display. Left-right motion was from - 600 to 658 mm. Clinicians stood on average 1000 mm from each other. The head roll angle was below 16[Formula: see text].

CONCLUSION

Surgeons were looking predominantly (99%) to the same display. Observations took place from fairly well-defined places and with sufficient potential to differentiate between clinicians, suggesting that single-viewer ASV would be feasible.

Screening for Stereopsis Using an Eye-Tracking Glasses-Free Display in Adults: A Pilot Study

Purpose:

To explore the feasibility and repeatability of a novel glasses-free display combined with random-dot stimulus and eye-tracking technology for screening stereopsis in adults.

Methods:

A total of 74 patients aged 18–44 years were recruited in this study (male: female, 32:42), including 33 patients with high myopia [≤ -6.0 diopters (D)] and 41 patients with moderate-to-low myopia (>-6.0 D). Stereopsis was measured using glasses-free, polarized, and Titmus stereotests. All patients completed a visual fatigue questionnaire after the polarized stereotest and glasses-free test. Kendall's W and Cohen's Kappa tests were used to evaluate repeatability and consistency of the glasses-free stereotest.

Results:

The stereotest results using the glasses-free monitor showed strong repeatability in the three consecutive tests (W = 0.968, P < 0.01) and good consistency with the polarized stereotest and Titmus test results (vs. polarization: Kappa = 0.910, P < 0.001; vs. Titmus: Kappa = 0.493, P < 0.001). Stereopsis levels of the high myopia group were significantly poorer than those of the moderate-to-low myopia group in three stereotest monitors (all P < 0.05). There was no significant difference in visual fatigue level between the polarized and the glasses-free display test (P = 0.72). Compared with the polarized test, 56.76% of patients preferred the glasses-free display and found it more comfortable, 20.27% reported both tests to be acceptable.

Conclusions:

In our adult patients, the new eye-tracking glasses-free display system feasibly screened stereopsis with good repeatability, consistency, and patient acceptance.

Metasurface holographic movie: a cinematographic approach

Animation for a metasurface hologram was achieved using a cinematographic approach. Time-lapsed images were reconstructed using sequentially arranged metasurface hologram frames. An Au rectangular nanoaperture was adopted as a meta-atom pixel and arrayed to reproduce the phase distribution based on the help of a Pancharatnam-Berry phase. We arrayed 48 hologram frames on a 2-cm² substrate and measured and assessed the retardation of fabricated meta-atoms to reconstruct the holographic image, successfully demonstrating the movie with a frame rate of 30 frames per second.

Using biomechanics to investigate the effect of VR on eye vergence system

Vergence-accommodation conflict (VAC) is the main contributor to visual fatigue during immersion in virtual environments. Many studies have investigated the effects of VAC using 3D displays and expensive complex apparatus and setup to create natural and conflicting viewing conditions. However, a limited number of studies targeted virtual environments simulated using modern consumer-grade VR headsets. Our main objective, in this work, is to test how the modern VR headsets (VR simulated depth) could affect our vergence system, in addition to investigating the effect of the simulated depth on the eye-gaze performance. The virtual scenario used included a common virtual object (a cube) in a simple virtual environment with no constraints placed on the head and neck movement of the subjects. We used ocular biomechanics and eye tracking to compare between vergence angles in matching (ideal) and conflicting (real) viewing conditions. Real vergence angle during immersion was significantly higher than ideal vergence angle and exhibited higher variability which leads to incorrect depth cues that affects depth perception and also leads to visual fatigue for prolonged virtual experiences. Additionally, we found that as the simulated depth increases, the ability of users to manipulate virtual objects with their eyes decreases, thus, decreasing the possibilities of interaction through eye gaze. The biomechanics model used here can be further extended to study muscular activity of eye muscles during immersion. It presents an efficient and flexible assessment tool for virtual environments.

Is the Glasses-Free 3-Dimensional Display System More Effective for Complex Video-Assisted Thoracic Surgery? A Self-Controlled Study Ex Vivo

Objective. Considering the demerits of a high-definition 2-dimensional (HD-2D) system, with its lack of stereopsis, and a conventional 3-dimensional (C-3D) system, which results in a dimmed image, we have recently developed a glasses-free 3-dimensional (GF-3D) display system for reconstruction surgeries such as video-assisted thoracic surgery (VATS) for tracheal reconstruction. Methods. Thoracic surgeons were invited to complete thoracoscopic continuous suture of a transected porcine trachea using the HD-2D, C-3D, and GF-3D systems on separate mornings in randomized order. The duration, numbers of stitches, and distance between every 2 stitches were recorded for every procedure. The surgeons' spontaneous eye blink rate was recorded for 5 minutes before the procedure and the last 5 minutes of the procedure. Results. Fifteen volunteers successfully completed the tracheal reconstruction procedures in this study. Both C-3D (0.403 ± 0.064 stitch/min, P < .001) and GF-3D (0.427 ± 0.079 stitch/min, P < .001) showed significant advantages in speed compared with HD-2D (0.289 ± 0.065 stitch/min). Both C-3D (2.536 ± 2.223 mm, P < .001) and GF-3D (2.603 ± 2.159 mm, P < .001) showed significant advantages in accuracy compared with HD-2D (3.473 ± 3.403 mm). Both HD-2D (1.240 ± 0.642, P < .001) and GF-3D (1.307 ± 0.894, P < .001) showed significant advantages in eye fatigue compared with C-3D (3.333 ± 1.44). Conclusions. All 3 available display systems are efficient for complex VATS. With the help of stereopsis, surgeons can achieve faster operation using C-3D and GF-3D systems in a thoracoscopic simulated setting. GF-3D may be a more effective display system for VATS reconstruction in terms of speed, accuracy, and eye fatigue during operations.