What is a key disadvantage when using sun glasses in illuminated areas for night vision?

The use of sunglasses in illuminated areas can significantly impede the eyes' ability to adapt to darkness. When entering a low-light environment after wearing sunglasses, the pupils remain constricted due to the tinted lenses, which can delay the adjustment needed for optimal night vision. This is particularly critical for tasks that require quick adaptation to darker settings, such as in military operations or nighttime navigation.

Sunglasses are designed to reduce glare and protect the eyes from bright light but are not conducive to environments where quick adjustments to light levels are necessary. As a result, the time it takes for an individual's eyes to acclimate to the new lighting conditions is prolonged, leading to reduced effectiveness during nighttime operations. Therefore, the inhibition of adaptation to darkness represents a significant concern for those frequently transitioning from bright to dark environments.