Nearly 10 million adults in United States severely nearsighted
Of those, nearly 820,000 have a degenerative form of the disease and more than 41,000 suffer a complication called myopic choroidal neovascularization that could cause long-term vision loss, with women at higher risk.
This is the first large-scale study ever done to calculate the real-world prevalence of myopic choroidal neovascularization in the United States.
Myopia has become increasingly common over the past several decades. In the United States, the number of nearsighted people rose from about 25 percent in the early 1970s to 40 percent around the turn of millennium.
While nearsightedness often can be corrected with eyewear or surgery, severe nearsightedness in which the eye continues to elongate can result in complications as the eye stretches.
Progressive high myopia, also called pathologic myopia, is a degenerative form of the disease. It can cause atrophy of the retina that lines the back of the eye.
People with high myopia and the degenerative form are at higher risk of myopic choroidal neovascularization. This condition is characterized by the growth of new, unstable blood vessels beneath the retina.
If untreated, it can cause vision loss that may then become permanent. As the prevalence of myopia continues rising, researchers are looking to better understand myopic choroidal neovascularization.
This study was conducted jointly by investigators from the American Academy of Ophthalmology, Genentech, the National Institutes of Health and UC Davis. Among the findings:
• Nearly 4 percent of adults in the United States have high myopia, defined as -6.0 D or worse in their right eye. That is equivalent to 9.6 million people.
• The prevalence of progressive high myopia is 0.33 percent. That is equivalent to 817,829 adults.
• The prevalence of myopic choroidal neovascularization is 0.017 percent. While the disease appears rare, it affects 41,111 people in the United States.
• Women appear to be at greater risk for complications of high myopia.
The prevalence rate for progressive high myopia was 0.42 percent in women compared to 0.25 percent in men.
An estimated 527,000 women have that condition compared to 292,000 men. Similarly, for myopic choroidal neovascularization, the prevalence rate for women is double that of men. ■