A recent US study has revealed that half of all Americans suffer from some kind of vision problem.

The study also showed that number of people suffering from vision problems is increasing day-by-day.

This study was conducted by the team at the National Eye Institute. The researchers analyzed the data collected from 12,000 people aged 20 and older between 1999 and 2004.

The researchers found out that over 33 percent were nearsighted and 36 percent had astigmatism. Another 3.6 percent Americans were farsighted.

The study also showed that half of the U.S. population 20 years or older suffer from clinically important refractive error.

Moreover, the study also showed that prevalence of myopia was higher than the 25 percent reported in previous U.S. studies.

Researchers added that the direct annual cost of refractive correction for distance visual impairment is estimated to be between $3.8 and $7.2 billion for persons 12 years and older.