How should divers use their eyes to adapt to low light conditions?

Divers should allow time for their eyes to adjust to darkness because this process, known as dark adaptation, enhances their vision in low-light conditions. When transitioning from a well-lit environment to a darker one, the eyes need time to adjust. This adjustment can take between 20 to 30 minutes, during which the photoreceptors in the retina, particularly rods, become more sensitive to low light levels. This increased sensitivity enables divers to see better and discern details in murky waters or during night dives.

Other methods, such as maintaining constant light exposure or using bright lights frequently, can hinder this adjustment. In fact, bright lights can cause temporary blindness when they are turned off, making it difficult for divers to see in the dark. Opening their eyes wider does not significantly impact the eyes' ability to gather light in low-light conditions, as the primary factor is the chemical adjustments in the retina during the adaptation process.