Studies examine rates of blindness and vision impairment worldwide

Reviewed by Emily Henderson, B.Sc.Dec 2 2020

Sobering new statistics released by the Global Burden of Disease study found no significant reduction in the number of people with treatable sight loss worldwide since 2010 as public health services failed to meet World Health Organization (WHO) targets.

Two studies published Dec. 1 in The Lancet Global Health examine rates of blindness and vision impairment worldwide in light of WHO goals to achieve a 25 percent reduction in avoidable sight loss in the decade leading up to 2020.

They found overall numbers of people both blind and vision impaired increased; adjusting for aging populations produced a 15.4 percent decrease in avoidable blindness since 2010, but no significant reduction in moderate or severe vision loss.

That puts global blindness and severe vision impairment on track to double by 2050. At that time, researchers estimate 61 million people will be blind, 474 million will have moderate and severe vision impairment, 360 million will have mild vision impairment, and 866 million will have uncorrected presbyopia, or farsightedness due to age.

Other key findings include:

• Cataracts are the leading cause of blindness worldwide, accounting for 15 million people or around 45% of global blindness.
• Except for glaucoma, the global prevalence of every major cause of blindness and vision loss is higher in women than men.
• Diabetic retinopathy was the only cause of blindness to show a global increase in age-standardized prevalence between 1990 and 2020.

John A. Moran Eye Center surgeon-scientist Mary Elizabeth Hartnett, MD, an author on the research who serves as a co-chair for the Presidential Commission on the Status of Women and director of Women's Eye Health, said the information paints a clearer picture of where efforts should be focused.

We have made some strides in reducing blindness, but we really have work to do to address moderate to severe vision impairment. It's crucial that we fund research to focus efforts on improving outcomes and to examine the unequal burden of blindness for women, including the root causes for disparity, the potential barriers to accessing care, and potential biologic differences. Additional data on childhood blindness is also needed."

Mary Elizabeth Hartnett, MD,  Study Author and Surgeon-Scientist, John A. Moran Eye Center

Since population growth is estimated to be greatest in countries designated by the United Nations as least developed, many in sub-Saharan Africa, it is important to train more eye doctors and nurses in these areas and to increase access to low-cost eyeglasses, said Hartnett.

The research underscores the need to upscale and replicate programs like the Moran Eye Center's Global Outreach Division, which works to create sustainable eye care systems in low resource nations and to reach underserved populations in Utah.

"Our program focuses on teaching and training surgeons, nurses, and eye care professionals around the world in a 'train the trainer' model," said Jeff Pettey, MD, Global Outreach Division co-medical director. "We've made key partnerships over the past few years that are allowing us to upscale that effort, and we are lending our expertise to peer institutions that can join the effort."

Moran outreach teams volunteer in low-resource nations to train ophthalmologists, nurses, and local health care workers during surgical clinics.

Trainees can also spend up to six months honing their skills at Moran. Working with international partners and governments, Moran can create low-cost, high-volume surgical centers of excellence. These centers then train other doctors and health care providers, exponentially expanding access to eye care.

As the largest program of its kind at any U.S. academic institution, Moran's Global Outreach Division has worked in more than 20 low-resource countries and partners with India-based Aravind Eye Hospitals, the world's largest eye care provider.

Moran has an ongoing effort in sub-Saharan Africa as teams work in Dodoma and Mwanza, Tanzania, to train physicians, nurses, and health care workers. Moran recently helped the University of Dodoma begin its first ophthalmology residency program.

Each year, the Global Outreach Division performs about 1,200 sight-restoring surgeries and 6,000 eye exams; gives away 3,000 free pairs of eyeglasses; and trains 30 international physicians and nurses.

In Utah, Moran provides vision screenings, eyeglasses, and sight-restoring surgeries on the Utah strip of the Navajo Nation. Charity surgery efforts assist low-income, uninsured Utahns, people experiencing homelessness, former refugees, and spinal cord injury patients.