Epidemiological model shows weak evidence for sleep apnea as cause for glaucoma

Addressing delegates attending the World Glaucoma Congress, Dr Mansberger, an ophthalmologist at Devers Eye Institute, Portland, Oregon, US, said that while there have been many case studies and anecdotal reports linking sleep apnea and glaucoma over the years, he thought it would be worthwhile to apply a more rigorous epidemiological approach to determine whether or not there was solid scientific evidence for the association. 'There are eight different factors that we look at as epidemiologists to decide whether a particular risk factor is related to the disease of interest. These epidemiological factors have been used to establish causation in areas such as electromagnetic radiation and silicon implants and can be applied to other areas of ocular disease as well,' he said. Dr Mansberger said that sleep apnea is usually defined as the average number of times a person stops breathing while sleeping, exceeding 10 per hour of sleep. The airway obstruction causes the level of oxygen in the blood to fall (hypoxia), and can contribute in some patients to hypertension, heart failure, stroke and other health problems. Going through the checklist, Dr Mansberger said that there was no real evidence to support the association between sleep apnea and glaucoma.