Visual impairment appears to be more common in people with diabetes than in those without the disease, according to a report in the October issue of Archives of Ophthalmology.
Approximately 14.6 million Americans had diagnosed diabetes mellitus in 2005 and another 6.2 million had undiagnosed diabetes, according to background information in the article. It is estimated that the number of individuals with diagnosed diabetes will increase to 48.3 million by 2050. "Diabetic retinopathy [damage to the retina caused by diabetes], one of the most common microvascular complications of diabetes, is considered to be one of the major causes of blindness and low vision," the authors write. Although studies suggest that controlling glucose and blood pressure have reduced the rate of retinal diseases, other ocular conditions suffered by diabetic patients, such as cataract and glaucoma, may increase the risk of visual impairment. Additionally, decreased vision caused by an abnormal shape of the cornea is also common among people with diabetes.
Xinzhi Zhang, M.D., Ph.D., and colleagues at the Centers for Disease Control and Prevention, Atlanta, used data from the National Health and Nutrition Examination Surveys from 1999 to 2004, which included 1,237 adults with diabetes (average age 59) and 11,767 adults without the disease (average age 45) and also measured their visual acuity before and after optical correction. Participants' vision was tested while they were wearing any glasses or contacts they typically used, and their demographic information was also noted.