After exposure to bright light, how long can dark adaptation take?

Dark adaptation refers to the process by which the eyes adjust to low-light conditions after being exposed to bright light. This process primarily involves the regeneration of photopigments in the retina, particularly rhodopsin in the rod cells, which are responsible for vision in dim light.

The adaptation involves several stages, and while initial adjustments can occur quickly, complete dark adaptation can take longer. In general, after exposure to bright light, it can take approximately 20 to 30 minutes for significant adaptation to occur. However, for full adaptation to take place, especially in individuals with normal vision, it can extend well beyond that, often between 2 to 5 hours.

Given this understanding, the answer indicating a duration of 2-5 hours accurately reflects the time required for complete dark adaptation, during which photoreceptor cells fully regain their sensitivity in low-light environments.