The effects of acceleration forces on night vision

Area of Science:

• Aerospace Medicine
• Human Factors Engineering
• Ophthalmology

Background:

• Cone-type mesopic vision is crucial for aviators, especially during night operations.
• Acceleration forces experienced in combat flight can impact physiological functions, including vision.
• Understanding these effects is vital for flight safety and performance optimization.

Purpose of the Study:

• To investigate the impact of specific Gy and Gz acceleration forces on mesopic vision luminance thresholds.
• To quantify visual performance decrements under simulated night-flight combat conditions.
• To assess the relationship between acceleration levels and visual acuity.

Main Methods:

• Experiment conducted on a three-axis human centrifuge (Dynamic Environment Simulator).
• Simulated acceleration environments: +1 Gz, +1 Gy, +1.4 Gz, +2 Gz, +3 Gz, and +2 Gy with +1 Gz.
• Visual task to determine 20/50 visual acuity illumination thresholds; physiological parameters (SaO2, heart rate) recorded.

Main Results:

• No significant shift in luminance thresholds observed at +1 Gy or +1.4 Gz.
• Significant increases in luminance thresholds (p<0.01) noted at +2 Gz, +3 Gz, and +2 Gy combined with +1 Gz.
• Physiological data (SaO2, heart rate) were collected but not detailed in the abstract's results.

Conclusions:

• Higher levels of Gz acceleration (+2 Gz, +3 Gz) and combined Gy/Gz forces significantly degrade mesopic vision.
• These findings highlight the critical impact of acceleration on visual performance in demanding flight scenarios.
• Implications for aircrew safety and operational effectiveness in night combat missions.