Many people in the U.S. are gradually losing their eye-sight due to conditions associated with nonrefractive visual impairments and type 2 diabetes, says a new study.

There has been an increase in the number of people who suffer from conditions like macular degeneration, diabetic retinopathy, glaucoma and cataracts.

"It is estimated that more than 14 million individuals in the United States aged 12 years and older are visually impaired (<20/40). Of these cases, 11 million are attributable to refractive error. In the United States, the most common causes of nonrefractive visual impairment are age-related macular degeneration, cataract, diabetic retinopathy, glaucoma, and other retinal disorders," says the study.

Researchers used data from the National Health and Nutrition Examination Survey (NHANES). More than 10,400 people above 20 years of age received questionnaires, laboratory tests and physical examinations in the years 1999-2002 and 2005-2008.

Analysis of the data revealed that the prevalence of nonrefractive visual impairment increased from 1.4 percent in 1999-2002 to 1.7 percent in 2005-2008 - an increase of 21 percent.

In non-Hispanic whites, there was a 40 percent increase in the prevalence of nonrefractive visual impairment, from 0.5 percent to 0.7 percent, researchers found. Although other factors like age, poverty and educational levels affected the increase, it was diabetes that was found to be a major contributor in the growth of people losing their eyesight.

"These results have important implications for resource allocation in the debate of distribution of limited medical services and funding. Continued monitoring of visual disability and diabetes, as well as additional research addressing causes, prevention, and treatment, is warranted," authors concluded.

In the U.S., the number of people being diagnosed with diabetes has tripled from 5.6 million in 1980 to 20.9 million in 2010. At present the U.S. economy pumps in $117 billion dollars in the treatment of diabetes each year. According to CDC by 2050, 1 in 3 US adults will have diabetes.

The study is published in the Journal of the American Medical Association.