Higher levels of physical exercise may have a long-term beneficial impact on low ocular perfusion pressure, a risk factor for glaucoma, British researchers say. Study author Dr. Paul J. Foster of the University College London Institute of Ophthalmology and colleagues examined the relationship between physical activity and current ocular perfusion pressure in 5,650 men and women age 48-90 who live in Britain and were part of initial cohort from 1993 to1997. The study subjects completed questionnaires on health and lifestyle and participants were assessed for combined physical activity at work and leisure. From 2006 to 2010, study participants were examined for eye pressure -- medically termed intraocular pressure -- and systolic and diastolic blood pressure measurements. The study, published in Investigative Ophthalmology & Visual Science journal, showed moderate physical exercise performed during a 15-year period was associated with a 25 percent reduced risk of low ocular perfusion pressure. \"It appears ocular perfusion pressure is largely determined by cardiovascular fitness,\" Foster said in a statement. \"We cannot comment on the cause, but there is certainly an association between a sedentary lifestyle and factors which increase glaucoma risk.\"