Changes in oculomotor functions before and after loading of a 3-D visually-guided task by using a head-mounted...

Area of Science:

• Ophthalmology
• Optometry
• Human Factors Engineering

Background:

• Head-mounted displays (HMDs) are increasingly used for immersive 3-D visual tasks.
• Potential impacts of prolonged HMD use on visual and oculomotor functions require investigation.
• Understanding these effects is crucial for optimizing user experience and visual health.

Purpose of the Study:

• To assess changes in visual functions, specifically refraction and ocular convergence, after a 3-D visually-guided task using an HMD.
• To evaluate alterations in the amplitude and velocity of convergence eye movements.
• To determine the impact of different disparity steps on these visual responses.

Main Methods:

• Eight young volunteers performed a 25-minute 3-D visually-guided task using an HMD.
• Measurements included the accommodation-convergence/accommodation (AC/A) ratio, stereo acuity, refraction, and ocular convergence.
• Ocular convergence was tested using varying disparity steps (0.7, 1.5, 3, and 6 degrees).

Main Results:

• No significant changes were found in the AC/A ratio or stereo acuity.
• Slight but significant hyperopic shifts in refraction were observed post-task.
• Mean amplitudes of ocular convergence changed significantly with disparity, decreasing at 0.7 degrees and increasing at 6 degrees. Peak velocities showed variable individual changes.

Conclusions:

• Short-term use of HMDs for 3-D tasks can induce small, non-pathological changes in refraction and ocular convergence.
• The observed changes in convergence amplitude depend on the disparity stimuli used.
• These findings highlight the importance of considering human factors in HMD design and usage to mitigate potential visual effects.