When virtual and real worlds coexist: Visualization and visual system affect spatial performance in augmented reality

Vision functionality and user comfort following the use of binocular indirect ophthalmoscope simulator

CLINICAL RELEVANCE

Headset-based simulator training is increasingly utilised in eye care education, offering opportunities to improve clinical skills in a controlled, reproducible environment. These tools support the development of innovative training approaches in eye care.

BACKGROUND

While the educational advantages of headset-based simulators are recognised, the potential challenges and limitations that users may encounter remain understudied. This study investigated changes in user comfort and vision functionality following a 40-minute headset-based simulator training of indirect ophthalmoscopy.

METHODS

Fifty-four participants aged 20 to 45 years (21 eye care professionals and 33 optometry students, analysed as a single group) underwent a 40-minute training session using the Eyesi binocular indirect ophthalmoscope simulator. User comfort with a custom-designed symptom questionnaire and visual functions using the RAF ruler, von Graefe technique, and prism bars were assessed before and immediately after the headset-based simulator training session.

RESULTS

Following the headset-based simulator training, there was a significant recession of both the near point of convergence (p < .001) and the near point of accommodation (p < .001). Baseline visual functions correlated with changes following headset-based simulator training, specifically near point of accommodation (r = 0.32, p = .02), horizontal near heterophoria (r = -0.37, p = .01), horizontal far heterophoria (r = 0.27, p = .04), blur point in positive fusional reserves (r = -0.61, p < .001), recovery point in negative fusional reserves (r = -0.36, p = .01), and AC/A ratio (r = -0.51, p < .001). Questionnaire results indicated a significant increase in discomfort following the headset-based simulator training (p < .001).

CONCLUSION

Forty-minute headset-based simulator training can lead to altered vision functionality and pronounced discomfort in some individuals, highlighting the variability in individual responses to training indirect ophthalmoscopy skills in video see-through augmented reality.

Individual Variations in Vergence and Accommodation Responses Following Virtual Reality Gameplay

Virtual reality (VR) can challenge the visual system, leading to temporary oculomotor changes, though the degree of change varies among individuals. While the vergence and accommodation system plays a crucial role in VR perception, it remains unclear whether individuals whose visual functions fall outside clinical norms experience larger changes. Thus, our study aimed to investigate whether changes in vergence and accommodation responses following VR gameplay differ between individuals with and without non-strabismic binocular and accommodative disorders. To assess this, both subjective and objective measurements were conducted before and after 20 min of playing Beat Saber. Results revealed significant alterations across both subjective measurements-near point of convergence and near point of accommodation-and objective measurements, including eye refraction, accommodation lag, and accommodative microfluctuations at far. Moreover, individuals with non-strabismic binocular and accommodative disorders exhibited larger accommodative microfluctuations at far compared to the control group. Overall, these findings indicate that considering individual differences in vergence and accommodation responses is important when evaluating the impact of VR on the visual system and can be helpful in the design and use of VR systems, particularly for individuals with binocular and accommodative disorders.

Why 2D layout in 3D images matters: evidence from visual search and eyetracking

Precise perception of three-dimensional (3D) images is crucial for a rewarding experience when using novel displays. However, the capability of the human visual system to perceive binocular disparities varies across the visual field meaning that depth perception might be affected by the two-dimensional (2D) layout of items on the screen. Nevertheless, potential difficulties in perceiving 3D images during free viewing have received only a little attention so far, limiting opportunities to enhance visual effectiveness of information presentation. The aim of this study was to elucidate how the 2D layout of items in 3D images impacts visual search and distribution of maintaining attention based on the analysis of the viewer's gaze. Participants were searching for a target which was projected one plane closer to the viewer compared to distractors on a multi-plane display. The 2D layout of items was manipulated by changing the item distance from the center of the display plane from 2° to 8°. As a result, the targets were identified correctly when the items were displayed close to the center of the display plane, however, the number of errors grew with an increase in distance. Moreover, correct responses were given more often when subjects paid more attention to targets compared to other items on the screen. However, a more balanced distribution of attention over time across all items was characteristic of the incorrectly completed trials. Thus, our results suggest that items should be displayed close to each other in a 2D layout to facilitate precise perception of 3D images and considering distribution of attention maintenance based on eye-tracking might be useful in the objective assessment of user experience for novel displays.