In bright light, the pupil constricts to reduce the amount of light entering the eye. In dark or dim light, the pupil dilates to allow more light into the eye to improve vision. Normal pupil size tends to range between 2.0 and 5.0 millimeters, depending on the lighting. The younger you are, the larger your pupils tend to be.
Fecal incontinence is commonly caused by altered bowel habits (generally diarrhea, but also constipation) and conditions that affect the ability of the rectum and anus to hold stool. The sphincter muscles become weaker as you grow older.
Fecal incontinence, when due to a temporary problem such as severe diarrhea or fecal impaction, disappears when that problem is treated. However, in some cases fecal incontinence can be severe and very difficult to control.