Which vision type has decreased acuity and color perception, usually occurring with partial moonlight?

Mesopic vision refers to the low-light conditions that occur during twilight or under partial moonlight, where both rod and cone photoreceptors are in play. In these lighting conditions, the acuity and color perception are decreased compared to photopic vision, which is the vision under bright light and relies primarily on cone cells responsible for color detection.

During mesopic conditions, the eye is not fully adapted to complete darkness like it is in scotopic conditions (full darkness), where the rods are dominant but color perception is extremely limited. In contrast, mesopic vision maintains some level of function for color and visual detail, but they are not as sharp as under photopic lighting due to the combined influence of both rod and cone function under dim light. Therefore, this visual type is uniquely characterized by its reduced acuity and color perception, fitting the description provided in the question.