How long does it take to get night vision?

The correct answer is 30 minutes because this is the approximate time required for the human eyes to fully adjust to low-light conditions, allowing for better night vision. This process is known as "dark adaptation," wherein the rods in the retina become more sensitive to light. During this time, the eyes gradually become capable of detecting lower levels of illumination. Initially, there is a quick adaptation phase, where some sensitivity increases can be observed within the first few minutes, but the most significant improvements occur around the 20 to 30-minute mark, reaching near-maximum sensitivity thereafter. This understanding is crucial for military operations, as right adjustments can greatly enhance a Marine’s ability to navigate and operate effectively in darkness.