Changes in ocular and visual variables during the menstrual cycle.

For most women the menstrual cycle is an integral part of a major portion of their lives. There is widespread agreement about the hormonal changes that occur during the menstrual cycle, but studies of physical and psychological changes have been more controversial. The influence of the menstrual cycle on various ocular and visual variables has been investigated. These include the potential protective role of female sex hormones in some ocular conditions, reports of reduced tolerance to contact lens wear, and changes in visual performance during the cycle. This paper critically reviews the literature on visual and ocular changes across the normal human menstrual cycle. Stereotypical views of an impairment of performance premenstrually and during menstruation are challenged. The shortcomings of, and difficulties associated with, much of the research on this topic are highlighted.