This condition is also referred to as Adie’s syndrome, where one eye experiences a dilated pupil (the circular opening in the center of the iris). The dilation might be irregular in shape. The affected pupil does not respond promptly to bright light, and even when trying to focus on different distances, it only partially responds. Although the cause of this condition remains unknown, it is most commonly observed in young women. Fortunately, it does not have any harmful effects on vision or overall health.