to WHO, cataract is the cause of blindness in more than half of the world’s total blind, accounting for blindness in about 20 million people in 2010.23 In 2010, one in three blind people was blind due to cataract, while it was the reason of visual impairment in one out of six visually impaired people.24 According to a study, the total number of blind people is expected to rise up to 75 million by 202025 out of which 30.1 million are estimated to be blind due to cataract.26 In a 2004 US study, cataract
tell if the findings are not biased by including the researchers’ opinion in questions that cannot be answered. In this case the study may lack rigour (Barbour,