Women in developing nations suffer from eye disease, but often for different reasons than those in the developed world.

Paul Courtright, one of the authors of a 2001 study that estimated the prevalence of blindness and vision impairment among women worldwide, attributes this in large part to gender equity issues and a lack of access to eye-care services.

"If we had gender equity in cataract surgery, for example, there would be at least six women getting surgery for every four men," says Courtright, who is co-director of the Kilimanjaro Center for Community Ophthalmology in Tanzania. "Most hospitals in Africa and Asia report the reverse mix: For every four women getting surgery, there are six men."

Women in the developing world also suffer disproportionately from trachoma, a bacterial infection that can lead to blindness. "Ninety percent of the cases are in women, and it is passed around through non-hygienic conditions around the home, often from mother to daughter," says Ilene Gipson, an ophthalmic researcher at Harvard.

Courtright's study identified women as having a 40 percent higher risk of blindness than men have, and "one thing we found very interesting was the fact that the pattern existed even among children," he says. "Boys were more likely to be brought for surgery for congenital or developmental cataract than girls. Boys were also more likely to be brought back for follow-up."

Courtright's center has treatment programs throughout Africa. In a global effort to address gender and blindness, it is also working with groups in India, Nepal, China, Egypt and other countries. "As populations improve socioeconomically, the disparity decreases," Courtright says. "There is still a long way to go, however."