USPA Skydiving B License Practice test

At what altitude can night vision begin to deteriorate?

1. 3,000 feet MSL

2. 5,000 feet MSL

3. 7,500 feet MSL

4. 10,000 feet MSL

The correct answer is: 5,000 feet MSL

Night vision can begin to deteriorate at approximately 5,000 feet MSL due to a combination of factors such as reduced atmospheric pressure and decreasing available light. At higher altitudes, the amount of light available from celestial sources diminishes, and the body’s adaptation to low light can be less effective. As altitude increases, there is also a reduction in atmospheric density, which can affect the visibility of objects against the night sky. At around 5,000 feet, many individuals may start to notice changes in their ability to see clearly at night because their eyes can take longer to adjust from bright light to darkness. This altitude is generally recognized as a critical threshold for night vision, especially in skydiving, where light conditions can change rapidly during descent. Understanding this altitude is crucial for jumpers, particularly when planning night jumps or preparing for landings under low light conditions. Proper training and awareness of these factors ensure safety and effective decision-making during night skydiving operations.