New research suggests that about half of 20 years or older adults in the U.S. suffer from refractive errors-eye problems wherein a sufferer has less than 20/20 vision.
Dr. Susan Vitale and colleagues at the National Eye Institute in Bethesda, Maryland, analysed data from the National Health and Nutrition Examination Survey (NHANES), an ongoing nationally representative survey conducted by the Centers for Disease Control and Prevention.
In-person interviews were conducted to collect demographic characteristics, and a vision examination was also carried out.
The analysis of the data about 12,010 participants, who completed the survey between 1999 and 2004 and had complete data available, showed that about half of them had some type of refractive error.
About 3.6 percent were farsighted, 33.1 percent were nearsighted, and 36.2 percent had astigmatism.
The researchers also found that nearsightedness was more common in women (39.9 percent) than in men (32.6 percent) among 20- to 39-year-olds.
People aged 60 and older were less likely to have nearsightedness, and more likely to have farsightedness and astigmatism than younger participants.
The study also showed that men (66.8 percent) were more likely than women (59.2 percent) in the older age group to have refractive error.
Mexican-Americans were less likely to have any type of refractive error (44.4 percent) than were non-Hispanic whites (53.4 percent) or non-Hispanic blacks (49.3 percent).
The prevalence of any refractive error increased with age, from 46.3 percent among those age 20 through 39 to 50.6 percent among those age 40 through 59 and 62.7 percent among those age 60 and older.
"Refractive error is, therefore, the most common condition affecting the ocular health of the U.S. population, involving young adults, middle-aged persons and older adults of all ethnicities," the authors said.
"Accurate, current estimates of the prevalence of refractive error are essential for projecting vision care needs and planning for provision of vision care services to the many people affected," they added.
The study appears in the August issue of Archives of Ophthalmology, one of the JAMA/Archives journals.