Recent epidemiological studies have revealed new insights into the pathophysiology of exfoliation syndrome (XFS). These studies found that lifetime and most recent residence in the northern tier of the United States (versus the middle and southern tiers) and with increasing latitude away from the equator are associated with increased risk of XFS.,, Ambient low temperature, ambient solar exposure, time spent outdoors (particularly in youth), and leisure or work activity over water or snow are associated with elevated risk of XFS.,, Sunglass, but not brimmed hat, wear decreases the risk of XFS.