DARK ADAPTATION, NIGHT VISION PROTECTION, CENTRAL BLIND SPOT

Question 1

DARK ADAPTATION

Answer 1

Dark adaptation for optimal night vision acuity approaches its maximum level in about 30 to 45 minutes under minimal lighting conditions.

Depending on brightness (intensity) and exposure duration or after repeated exposures, complete dark adaptation recovery time can range from several minutes to 45 minutes or longer.

Exposure to intensesunlight for 2 to 5 hours decreases visual sensitivity for up to 5 hours and also decreases the rate of dark adaptation and degree of night visual acuity. These cumulative effects can persist for several days.

Question 2

NIGHT VISION PROTECTIVE EQUIPMENT AND MEASURE

Answer 2

Sunglasses

Red-lens Goggles

Supplemental Oxygen over 4000ft PA

Cockpit Light Adjustment

Exterior Light Adjustment

Light Flash Compensation

Question 3

CENTRAL BLING SPOT

Answer 3

The night blind spot should not be confused with the day blind spot. The night blind spot occurs when the fovea becomes inactive in low light conditions and involves an area from 5 to 10 degrees wide in the center of the visual field. An object viewed directly at night might not be seen due to the night blind spot; if the object is detected, it will fade away when stared at longer than 2 seconds. The size of the night blind spot increases as the distance between the eyes and object increases. Therefore, the night blind spot can hide larger objects as the distance between the observer and object increases.