Thursday is World Sight Day, and international agencies are raising awareness, and money, to prevent blindness around the world. Health officials say up to 80 percent of cases of blindness and visual impairment can be avoided.
The World Health Organization says more than seven million people go blind every year and most of these people are in the poorest countries.
Derek Yach of the health organization says if governments would pay more attention to eye care and more money was made available, many cases of blindness and visual impairment can be prevented.
"When you see a high proportion of blindness in a community, you know that many other things are not going well, whether it is on the nutritional side, development, high levels of infection," he said.
Dr. Yach says the major causes of blindness are cataract, which is a cloudiness of the eye lens stopping light from entering the eye, and eye diseases like trachoma, caused by bacterial infection, and river blindness, caused by a parasite.
Dr. Yach says improved sanitation, face washing and antibiotics can treat trachoma, while a medicine called Mectizan can stop river blindness.
Mike Whitlam of the International Agency for the Prevention of Blindness says great progress has been made during the past 15 years in controlling river blindness in West and Central Africa, and he adds that with more money and political will, other eye diseases can be cured.
"This is not us envisioning something that cannot happen," he said. "We have examples of good practices that have been going on for quite a long time and that is just one example of the kind of program that shows that we can make a massive impact amongst people who are needlessly blind."
The World Health Organization and the International Agency for the Prevention of Blindness say together they spend more than $100 million a year to help prevent blindness. They say that if they had another $100 million they could save the sight of many more people in the developing world.