1.4 million Nigerians over the age of 40 will become blind by 2020: Study

84 percent of all causes of blindness are either preventable or treatable, study finds

By 2020, 1.4 million Nigerians over age 40 will lose their sight, and the vast majority of the causes are either preventable or treatable, according to the Nigeria National Blindness and Visual Impairment Study Group.

In the September issue of Investigative Ophthalmology and Visual Science, the group shares the second half of the results of the study, which examined almost 15,000 Nigerians over 40 between 2005 and 2007. The goal of the study (Causes of Blindness and Visual Impairment in Nigeria: The Nigeria National Blindness and Visual Impairment Survey) was to help Nigeria create a plan for its participation in the World Health Organization's VISION 2020: The Right to Sight Initiative, which is working globally to eliminate preventable blindness. The first half of the study appeared in Investigative Ophthalmology earlier this year.

About 23 percent had some sort of visual impairment, and 4.2 percent were blind. Cataracts were the most common cause of blindness, with glaucoma second. Refractive errors (which cause nearsightedness, farsightedness and astigmatisms) were frequently the cause of less serious visual impairments. Other common treatable or preventable causes of visual impairment included complications from diabetes, trachoma (a bacterial infection of the eye) and the parasite onchocerciasis, which is transmitted to humans through the bite of a black fly and is prevalent in Africa.

"The high proportion of avoidable blindness - means that appropriate and accessible refraction and surgical services need to be provided," the report states. "If priority attention is not given, the number of blind and severely visually impaired adults in Nigeria will increase by greater than 40 percent over the next decade."

The study noted that groups that had less access to health care were particularly vulnerable to preventable visual impairment.

According to the study, "The difference in the prevalence of vision loss due to cataract between men and women, urban and rural areas, and levels of education in Nigeria almost certainly reflects access to services." The authors recommended vision care plans that target women, rural residents and the less educated.