Advancing vision standards in aviation: Embracing evidence-based approaches.

Area of Science:

• Aviation safety
• Human factors in aviation
• Ophthalmology

Background:

• Pilot visual requirements are critical for safe flight operations.
• Existing visual standards may not fully account for performance decrements under varied conditions.
• Understanding the relationship between visual function and flight performance is essential.

Purpose of the Study:

• To determine the minimum visual requirements for safe pilot performance.
• To explore the impact of visual acuity and contrast sensitivity degradation on flight performance.
• To assess performance in simulated poor weather conditions.

Main Methods:

• Twenty-six pilots with varying experience flew simulated circuits with induced visual degradation (scattering/defocus).
• Flight performance was assessed objectively (simulator data) and subjectively (instructor evaluation).
• Visual acuity and contrast sensitivity were measured under different degradation levels and simulated weather.

Main Results:

• Pilot performance, including vertical speed and altitude control, significantly varied with vision degradation and weather.
• Defocusing lenses and scattering lenses affected flight performance at specific visual degradation levels (1.3 and 1.0 logMAR, respectively).
• The type of vision degradation (scattering vs. defocus) also impacted the slope of altitude descent.

Conclusions:

• Current visual standards for pilots may require reevaluation to be more evidence-based.
• Specific levels of visual acuity and contrast sensitivity degradation significantly impair flight performance.
• This research provides data to inform updated visual standards for aviation safety.